[BB_TX]

If they have the same insurance carrier and the exact same plan then it probably has to do with their family/economic status. The gov gives a certain amount of credit (subsidizes but they don't like that word) to each person based on income, family size, single/married, etc. Those subsidies can be significant.
Personal health insurance if you are not yet 65 is extremely expensive. Since I retired at 62 (and DW is 2 yrs younger) we had to bite the bullet and fork over a significant sum each year for health care. Was like getting a big raise in income when I turned 65 and again when she did. We now have Medicare primary and BCBS/TX as our supplement (plan F) and pay very little out of pocket for care.
As mentioned, whatever you get make sure you get a PPO to avoid problems finding proper care when you need it. And one that will cover you where ever you may be if you full time and may be in any given state at any time.
If you seek obamacare, the healthcare.gov web site will ask you to select your state and county when you begin to look for plans. Don't know how that affects someone who does not have a S&B residence.