Here are some of the results I found. I used to be in the same situation as you and I used SHARPMEDS.com online. They are a Mexican pharmacy that uses FDA certified labs. All their stuff comes in factory packaging so it's like the samples you get at the Dr's office. Anyway, heres a comparison for those that are interested in shopping for price.
COSTCO CVS SHARPMEDS.com
Avandia 4 mg - 120 tabs $371.56 $375.96 $85.00
Sharpmeds is generic Rosiglitazone
Glipizide 5mg ER - 120 tabs ~$35 ~$65 $29.90
Lipitor 40mg - 100 tabs $161.23 ~$185 ~$88
Costco & CVS based on 80mg pills split with pill cutter
Anyway, you get the picture. Some products you can save tremendously cross border and some not! I have personally used this website and they are reliable and the meds you get work just like the ones from CVS (the only thing is the shipping can take upwards of 3 weeks).
I'm not advertising a website but simply giving you the results of what I found when it was pay the rent or pay for my meds time for me!