A Kaiser Health News analysis of costs in the three-dozen states selling policies through the federal healthcare.gov website found a sharp difference in premium prices between plans that offer out-of-network care and those that do not. The analysis compared the monthly premiums for the least expensive silver-level plans — the category that are the most popular purchases — for a 40-year-old in each county. While the average premium for the least expensive closed network silver plan—principally HMOs—rose from $274 to $299, a 9 percent increase, the average premium for the least expensive PPO or other silver-level open access plan grew from $291 to $339, an 17 percent jump, KHN found. The cost variations hold true for any age.