Yes, unfortunately, the labs are the most expensive.
Comprehensive Metabolic Panel est. $200 (everybody should get one a year for Physical anyway).
Complete Blood Count est. $30 (more with diff. Usually unnecessary).
Total Testosterone est. $100 (more with free-T/DHT. Usually unnecessary).
Estradiol est. $50 (occasionally necessary to get).
Generally, you're looking at four sets of these the initial year (excluding prelims - typically just the CMP and CBC), as your dosage is being adjusted to suit you. IF there are no problems and IF you have a doc that knows what they are dong, you'd really only need them biannually the following year or two, and after that once annually for the remainder of your TRT (unless there is a problem down the road).
With the exception of the CBC. That one is actually the foremost important and it should be had regularly (optimally quarter-yearly). That is because the premiere risk of TRT is too many red blood cells. And it can develop at any time, with or without any dosage/administration alterations. And if it does, you'll also need to make further adjustments to your TRT and that means more rounds of the others to do it.
Otherwise, an Endocrinologist will be more expensive than a GP. $100-200 I'd estimate. You MAY be able to find a GP willing to oversee your TRT, just know that most are not comfortable stepping outside of their general area of expertise. Worth a try though. Some will, some won't. Some will IF you start initially with an Endo and then take over after the preliminary adjustments have been figured out and made and there's no problems. YMMV.
But, many specialists do volunteer at low/no cost clinics. If you can, do try to find an arrangement like that. The clinic itself, on the clerical end, can be a right pain to deal with, but the specialists there know what they're about, usually... unless they're training (had some problems. It's the price you pay to sort them out). Oh, and time... I sit for 6 hours every 3-4 months. Always have errors at the clerical end with my prescriptions as well but again, that's the real cost of clinics, and ultimately well worth the hassle.
Additionally, believe it or not, but you'll have better luck at a COUNTY hospital/clinic for this. They've had more experience with us than any small clinic. This is of course providing you're not close enough to an actual LGBTQ clinic (nearest to me is nearly 200 miles round trip so...).