Becky Cowdery's family received two blessings in 2015.The first, she said, was when surgeons removed a cancerous tumor from her husband's esophagus.The second was when strangers helped pay the bills.Six weeks of chemotherapy and radiation, two surgeries and a 19-day hospital stay had left the Tampa family more than $15,000 in debt. But it wasn't long before checks from across the country started arriving in their mailbox, some accompanied by notes of prayer and encouragement."It could have been disastrous," she said. "We saw the Lord take care of us in a huge way."The Cowderys are members of a health care sharing ministry, a little-known but fast-growing alternative to health insurance allowed under the Affordable Care Act. Members "share" their medical expenses — and usually pay far less in monthly fees than consumers with traditional health plans.There are some caveats: Most health care sharing ministries are open only to church-going Christians who agree not to smoke cigarettes, use drugs or have sexual relations outside of marriage. And some services aren't covered, including abortions, fertility treatments and maternity expenses for children conceived out of wedlock.Since the Affordable Care Act upended the health insurance landscape in 2010, health care sharing ministries have experienced a surge in membership. An estimated 450,000 Americans are now participating, according to an industry group.But some consumer advocates say the "plans" are a risky bet. The nation's four largest health care sharing ministries remind members they aren't insurance companies — and payment of their medical bills is not guaranteed."Many of these ministries have now gotten so big you don't know who you are sending (the money) to," said Sabrina Corlette, project director at Georgetown University's Center on Health Insurance Reforms. "You have to hope and pray that if something happens to you, people will hold up their end of the bargain."• • •There are four major health care sharing ministries in the United States. Each operates a little differently.To join the Medi-Share program, run by the Florida-based Christian Care Ministry, prospective members are asked to sign a statement of faith and follow the code of conduct.Restrictions such as the ban on drugs and smoking are in keeping with biblical principles, CEO Tony Meggs said. But they also help keep medical costs down."There's a financial windfall when you're not worrying about diseases that result from tobacco use," Meggs said.Medi-Share is not unlike a traditional health insurance plan. Members choose one of several monthly "share" amounts (akin to a premium) based on the amount they plan to contribute toward their medical bills before the benefit kicks in (akin to a deductible). The more an individual or family is willing to contribute, the less expensive the share.Members must pay for their own annual check-ups and maintenance drugs. But they can submit any other medical expenses to the ministry to be shared among the membership.Unlike traditional insurance, the money is never pooled. It goes from one Medi-Share patient account to another. The electronic accounts are managed by Christian Care Ministry. Members are told who they will be assisting — or receiving assistance from — so they can offer prayers."In the early church, people came together every day and shared their resources," Meggs said. "They made sure nobody went without need. (Medi-Share) is a practical, real-world application of that idea of sharing our resources with each other."• • •John and Becky Cowdery first discovered health care sharing 20 years ago. The couple had recently given birth to their first child — and had a stack of health care bills waiting. A friend mentioned Illinois-based Samaritan Ministries."We thought that was an awesome concept," Becky Cowdery recalled. "It was also very affordable to us."Unlike Medi-Share, members of Samaritan's program receive a monthly letter identifying a family with a need, and send their "share" check directly to that family.All members pay the same amount based on the size of their family. And there's no deductible, per se. Members can submit any medical expense that exceeds $300 for sharing.The Cowderys had submitted their bills when their next three kids were born, and when their son broke his arm. Everything was paid. But nothing had been as serious as John's cancer diagnosis in July 2014.John Cowdery had some coverage under a Florida Blue plan his company offered free of charge. However, he still had to meet a $15,000 deductible — a significant financial burden for the family. John Cowdery is a painter for a home building company. Becky Cowdery is a stay-at-home mom.They paid their remaining bills up front, and then sent them to Samaritan for sharing."I was little bit worried," Becky Cowdery said. "It is not a guaranteed thing. The whole thing was by faith."She and her husband prayed the checks would arrive.• • •Health care sharing is experiencing a boom.Over the last five years, Medi-Share's membership has nearly doubled, Meggs said. It now includes 160,000 individuals, more than 8,000 of whom live in Florida.Samaritan Ministries saw its membership jump from 48,000 people to more than 165,000 people over the same period, executive vice president James Lansberry said.The growth is largely the result of the Affordable Care Act's "individual mandate." The provision, a linchpin of the health law, imposes a fine on individuals who do not have health insurance.Before the law passed in 2010, a group called the Alliance of Health Care Sharing Ministries lobbied Congress to exempt members of health care sharing ministries from the penalty. Thanks largely to support from conservative lawmakers, their efforts were successful.But the language effectively made health care sharing ministries of all faiths a loophole for people seeking to avoid expensive insurance premiums.Ann and Willis Michell of Gulfport were among the thousands who joined a health care sharing ministry last year. Their decision was driven largely by cost. The couple used to have a Florida Blue plan they had purchased on the individual insurance marketplace. But after the premium spiked in 2014, they began looking for other options."We were going to be paying $24,000 a year with a $6,000 deductible per person," Willis Michell said. "That's just insanity."Their monthly share with the Ohio-based Christian Health Care Ministries is $300. They see it as a bridge until they qualify for Medicare next year.The Michells, who are active at the First Baptist Church of Indian Rocks, like the faith-based aspect. But they also know better than most how expensive health care can be — and what huge medical bills can do to a family's finances. Both are retired registered nurses who volunteer at free health clinics in Pinellas County."We're kind of taking our chances," Willis Michell said. "But I think it's about the best we can do."• • •Consumer advocates have raised a litany of concerns about health sharing ministries.Corlette, of the Georgetown University Center on Health Insurance Reforms, pointed out that most states, including Florida, exclude health care sharing ministries from the state insurance code."With your Humana plan or your Cigna plan, there's a cop minding the beat; there's a state official looking over the insurance company's shoulder, making sure they have enough money to pay the claims," she said. "There's none of that independent oversight of the health care sharing ministries."Ministry leaders say they are clear they are not offering insurance. The Christian Care Ministry web site says so more than 2,000 times, CEO Meggs said."The fact is, there's no guarantee and there's no promise to pay," Meggs said. "You are really just relying on a community of like-minded people."Becky Cowdery is a believer.Seven months after her husband's surgery, he is cancer free and the family has no medical bills.Contact Kathleen McGrory at [email protected] or (727) 893-8330. Follow @kmcgrory.