Tricare is also run as a health insurance company. Those who can pay premiums like any other health insurance customer, those who can't are treated through the VA system.
Not entirely true, I will say it is run as a HealthCare insurance there are 4 Tricare regions 3 regions cover the US proper and 1 region called overseas, each region is administered by a Healthcare Insurance provider: North - Health Net, East - Humana Military, West - Unitedhealthcare Military, Overseas - International SOS.
Tricare is a 3 tier system for Active Duty, Retirees and their dependents.
There are 3 levels:
Standard, Extra, And Prime (all of them have different levels like Prime Overseas, Prime Remote), then there is Tricare Young adult(for dependents over 23 who are still in Undergrad, grad school, Law School, Med School or any other school that takes them past age 23 to age 26) and Tricare for life(This is after the sponsor turns age 65 and is eligible for medicare, at this point medicare becomes primary and Tricare becomes secondary.
Here's how Tricare works: As an active duty servicemember you are automatically enrolled in Tricare Prime and so is your Family members, cost $0, you receive treatment at military hospitals, clinics or satellite clinics. Now if you are REFERRED to an outside civilian medical facility the cost is $0, if you go on your own Tricare will pay 80% and you pay 20%.
For retirees, Prime cost $495 a year plus deductible and co pays. You have a primary care manager and need referrals to see a specialist
Extra is free the only difference is the deductible and co pays. You can be seen at a military hospital or clinic or Satellite clinic at no cost
Standard is also free, a little high deductibles and co pays but no referrals needed. You can still be seen at a military Hospital, clinic or Satellite clinic.
Going to VA is a choice made by service members who feel or were told that their medical problems were service related and they need to try and get a percentage of VA disability(portion of any military retirement that will be deemed tax free due to disability) Once in the VA system all your healthcare is handled at VA clinics and VA Hospitals unless it is a life threating emergency then if the Military Hospital is available and the needed specialty is there you will go there, if not, the nearest civilian facility, or you can request transfer or the attending Dr. may decide to send you to Brooke Army Medical Center, Bethesda, Walter Reed but only in the direst of health problems ie Transplant.
So you see it's not based on whether you can pay or not it is based on what your choice is. For our family Myself and my wife we have Tricare Standard, and purchase a Tricare supplement, and we have just purchased Tricare Young Adult for my daughter who turns 23 next month and will be in Graduate school. Next year we go to Tricare for life as I will be 65, and I will also have Medicare, but I have to purchase part B. We get all of our care at either William Beaumont Army Medical Center(emergencies or weekend Quick Care) or the Vista Del Sol WBAMC satellite clinic(our primary care Dr is there). My oldest daughter has Tricare Prime as she is the wife of a Soldier.
Okay that is TRICARE at a glance.