I looked up how much Zoladex, my analogue blocker, cost- in an outdated book, the monthly dose was about £80 ($160 -ish), with inflation I expect a touch more expensive now. And I believe that was a base rate, and not a consumer rate.
What you want to do is the path you are forced to take on the English NHS, a year of hormone blockers and then you go on T. I'm about two and a half weeks after my first injection and there has been no change, I got my period about two days after injection. I think the effects are gradual, hoping it will kick in more next month after my second injection. So as far as safety, it's fine, and I have heard that it's like a blank slate for T to start on, without 'battling' the female hormones, so changes on T might come about faster etc with less mood swings due to hormone madness.
If you do go on HB, it's advised to take a vitamin d supplement to reduce any negative effect to bone density. As for side effects, it's meant to be a bit like a menopause - hot flushes and such. As I have said, so far, everything's been normal.
