You don't have to be a citizen here to receive medical care, you just have to have appropriate insurance coverage or be willing to pay out of pocket for whatever you need.
As far as costs go, you'd be paying for (1) doctor visits, (2) blood work, (3) testosterone, and (4) needles. This is all going to vary based on where you go, where you're located, etc. To give you a rough idea:
- My doctor visits are covered by my insurance. I pay $30 to see my doctor quarterly (every 3 months). If I did not have insurance, my doctor visits would cost $200. This office operates on a sliding scale though, so if I could not afford to pay $200 and I didn't have insurance, they would base the fee on my income.
- My blood work is done a week before I go to the doctor, every 3 months. With insurance, it costs $10 to run the tests my doctor requires. Without insurance, it would be around $550 per visit. These are not covered by the office's sliding scale, so while the visit would be cheaper if I couldn't afford it, blood work would still need to be paid for somehow. After 1 year on HRT, my doctor only requires annual visits with blood work, so this would go from being a 4x a year expense to just one.
- My testosterone is covered by insurance in 1 month dispenses. That is inconvenient for me, so I pay out of pocket for a multi-dose 10ml vial. It lasts around 5 months for me and costs around $50. The price fluctuates month to month.
- Needles are around $10 for a 24-pack of drawing syringes and a 24-pack of injecting syringes through the pharmacy at my doctor's office. You could probably save more on them buying in bulk online if you're able.