Yeah i'd definitely look into the total costs and shop around. I do not know for sure because i pay nothing at present for mine but it seems to me when i was buying them at full retail it was something like $125-$150 per month. That amount may be palatable or at least low enough that an additional part time job, or activities like selling stuff on eBay, could cover it.
Also check with your doctor, he or she may know of clinics or options like planned parenthood and others that offer HRT free, discounted or on a sliding scale.