I work in a pharmacy, so I thought I'd weigh in here even though I'm not on T (yet).
-The cost will vary by your needs and the form of T you are taking. Vials come in different sizes and can vary in price. Someone also mentioned above that syringes may or may not be included with your medication. I'd recommend buying them from a medical supply place in bulk. Make sure to order the right kind. DON'T attempt to use insulin syringes for your hormone injections. That's a bad idea! You may be prescribed T gel as well, which is applied topically and prescribed in different amounts from the vials. There is also a T patch available. I have not seen this, but I do know that it exists.
-Another thing to consider is that you may not be prescribed standard T that you can get at any pharmacy. Some people may have to have their T compounded (custom mixed according to prescription). That may run you a bit more or a bit less than a standard scrip, depending on location and insurance. There are a few good online compounding pharmacies. If you're seeing an endo, they will usually have a go-to compounding pharmacy in their area that they will refer you to if you need your prescription compounded.
-Not all insurance plans will cover your T. At my workplace, I've dealt with one particular insurance company that does not cover these sorts of treatments for transfolk. I've not had experience with any of the other healthcare plans refusing, but I do know that it is something to be aware of. You should ask your provider if they cover it, what percentage, what forms, etc. Another company I've worked with does cover hormone treatments, but only certain brands/forms/amounts. It's a pain, but do your best to verify that your T will be covered by your insurance if you have it and plan on using it.
-There are labs that do not require doctor's orders and offer a variety of tests online. These places operate their own labs and are pretty basic, but they will get the job done for a fraction of what you'd pay at a standard lab. Just search for "blood testing services online" or something of that nature and it will pull up a few places. This sort of thing is not available in all states, though.
Hope this helps.