1000 pieces on eBay will almost always cost you less than whatever Michaels is charging for its tiny package, so you might as well. There's often packs of 100 too, just takes some digging through the listings. Can always donate the excess to your local thrift store or maybe you have a friend who's into crafty stuff and wouldn't mind adopting the extra?
What are you using 'em for? I recently bought some red and black glass rhinestones as upgrades for ruby/ore tokens, not a big fan of plastic pieces.
I've used the super small nail gems on 40k Marines; on the old metal terminators they work great on the belt part. They're also good for enhancing a treasure pile or adding some bling to a shield or other item that may have a magic gem on it. The Swarvoski ones are very sparkly and since they came in 20 packs it's more than I'll use in years. I've thought about using them as the eyes on a dragon too; going to start my Clockwork Dragon and crystals for eyes goes with the theme.