very few insurance companies will cover propecia because it is prescribed for hair loss 99% of the time. the drug was created to cover propecia.
a lot of companies will cover proscar because it is typically prescribed for the prostate but it is insurance fraud if you submit a claim for coverage for any reason other than prostate. if you are lucky maybe your doctor will write it for you to use as directed and then your insurance company will probably cover it. if you take your script to a pharmacy and they run it through your insurance and they cover it then you aren't legally liable for it. it's only if you have to submit claims yourself and you lie that you could be in legal trouble.
a few companies will cover a portion of the avodart cost for hair loss.