i'm not sure of the cheapest but i've gotten mine from firemountaingems which seems pretty reasonable.
then again, i don't buy super large quantities
The 50+ price break at Fire Mountain is on par with the 1 pk price at Rio Grande, but Rio doesn't have quite the selection.
I like Fusion Beads for Swarovski Crystals. Their regular prices seem to be a little cheaper than Fire Mountain's regular prices, and they offer a discount the more you buy.
Gerri's Crystal does very good deals for real wholesale orders, smaller orders are retail, like everyone else.
I don't have the link on hand but do a google search for it.
Try INM Crystals. They also run monthly specials for the birthstones.
Oh...and ArtBeads.com does free shipping and no tax. Sometimes that helps if you figure the other companies shipping can be that you end up paying more for the item.
I don't buy large quantities either :-( Cant afford to at this time, So i also would love to know the cheapest places, I've ordered from Firemountain but thats all.
The prices across the board are not the same.
For example: a 6mm bicone might be cheaper at source A, but their (source A) 6mm round could be more expensive than at source B.