Where do people find they can buy vitamins the cheapest? Wal-mart or some other type of online retailer?

You will find cheap vitamins online and at Walmart, but for a good tasting and quality product that meets your new needs, you might want to compare their prices and product to companies that specialize in bariatric formulas such as Celebrate Vitamins and Bariatric Advantage. IMHO Celebrate tastes pretty good. I tried to go cheap on the whey protein and only ended up wasting money because I didn't really like the taste. I finally caved in and got the good stuff at a higher price, but it taste good and it's making my full liquid phase just a tad more bearable. I figure that I'll use the money I save on eating out to splurge on my vitamins and protein.

Drugstore.com

Trader joes chewable multi is $7-8 for 45 days worth (90 tablets)

puritainspride.com has great prices and a money-back guarantee if you don't like them.