I get a 30 day (1.5 grams twice per day) supply of Metformin at Walgreens for < $5.
OT, but how did the brand name Glucophage get approved? I don't see how calling a drug "glucose eater" is anything but misleading.
In general, stimulants were once more popular as apatite curbing agents. When the drug was developed, they probably thought people would use it to lose weight, so 'glucose eater' has the same general effect they were going for: weight loss.