Finasteride is cheap. Can be under $10/month depending on how you do things, dose etc.
5mg is the standard dose for prostate cancer, and 1mg for baldness. So people buy the 5mg pills (which are cheaper), and cut them with a pill cutter, which are cheap. It is then less than $10/month.
Difficulty of a prescription depends on the doctor. The first doctor I went to wanted to do expensive blood tests, to make sure I didn't have a nutritional deficiency. He then said a whole lot of other garbage that I discussed elsewhere.
The second doctor I went to said "yeah, you have temple recession", and wrote me a prescription. A good doctor can distinguish between male pattern baldness and alopecia areata or hair thinning from nutritional deficiencies based on the pattern of baldness on your head.