I pay for mestinon as a generic and my co-pay for generics is $20 for 90 days. Maybe 18 years ago, mestinon wasn't a generic yet? I don't know when it was initially developed and for the first 7 years, the drug companies can pretty much charge what they want. After the first 7 years, generic competition causes the price to go down. But, on second thought, I don't know if that would apply to mestinon since my understanding is that only one company manufactures it. Hmmmm???