As a retired pharmacist I would suggest that you go to an independent pharmacy and speak with the owner pharmacist about your medications. The chains often sell the top 100 or 200 medications at deep discount (not below cost as that is unlawful in most states) but certainly really cheap. In exchange they make a substantial profit on other medications. A few older medications which have been generic for years have been reviewed by the FDA because the current required levels of testing were never preformed. These drugs were then removed from the market until a company, any company, spent the millions required to bring the tests to current levels. That company was then given the exclusive on the new Branded product.
As for your $5 co-pay: In my humble opinion that was the beginning of this whole mess in the first place. When I entered pharmacy patients paid the full price of their medication. The national average price was below $4 per prescription. Companies were hesitant to charge to much for new medications because the public would not accept the expense. Keflex, by Lilly was the very first medication in the USA to break the $1 per dose ceiling. When insurance companies starting paying for the medication and the patient only paid a co-pay the cost of medication became hidden from the public. Now drugs could be $100 or more but no one complained since they only paid $5. Ads on TV and in print encouraged people to take the new drugs "covered by most insurance plans." Now new drugs, like the medication for Hep-C, although life saving and life changing, are coming to market at thousands of dollars per dose. $80,000 for a course of therapy. Justified by the fact that $80,000 is less than the insurance company would have to pay for lifetime treatment of an active Hep-C patient with pending liver failure.
Just a little history.
Good Luck