If you find a doctor that accepts your insurance, TRT can be very affordable. Flexibility when it comes to lab work will depend on the doctor, but I don't see that being an issue for most. Typically, the doctor writes a lab order that the patient takes to a lab of their choice.
Same goes for prescriptions. The doctor writes a prescription which the patient takes to whatever pharmacy they choose.
If you end up going to a clinic there are often more restrictions, and the cost is definitely going to be higher.