Hey, vlkr, what is the deal on foreign drugs? Is it legal to carry them back with you but not legal to order them outside the country and import them?
Without script, the Customs rules specifically prohibit bringing back prescription meds. With script, okee dokee

as long as the drug is allowed. If it's not, there may well be very good reason it's not.
From overseas, like the camp light I once suggested you order from Hong Kong - small package mail arrives by truckloads and they really can only check a small part - looking for controlled substances mostly. If they find prescription meds, they really lack abilities to check for counterfeit, and the packages are simply returned to sender.
The big difference to the US buyer is that airport store doesn't care if you are happy or not after you leave, while the overseas supplier counts on repeat business. I have tried some that I didn't like the looks of, threw them out and got my money refunded. I've been obtaining one med from my usual supplier for 4 years now at dramatic savings.
You've probably noticed that prescription drugs in the US are seldom in the blister packs like sold in Mexico and overseas commonly. Those packs are an efficient way of handling that lowers costs, but in the US - highly paid pharmacists and techs count and pack each order usually, running the costs up along with drive up windows, call-in scripts, and so forth. As said above tho,
your meds are largely paid by your PCS card, funded by your insurance provider who is paid by your employer, so the costs are hidden. Elsewhere, buy the package that closely resemble your needs, preboxed, while you are in the store.