If your perfectly fine building with a random bunch of parts, then we’ve got a couple eBay listings that may be worth a look. You can probably get bulk random parts much cheaper by hunting down local deals with a local LEGO User Group, so be sure to check if you have one in your area.

For $24.75 and about 8 bucks shipping, this listing for a pound of parts is not a bad looking deal. It looks like a good mix of classic and CCBS BIONICLE, though the seller has not done a perfect job picking out the non-LEGO parts and some brick pieces have made their way in. I might not complain about getting the Creeper minifigure, or the limited edition Nerf Rival H.I.R., though you might expect to get a few curiosities mixed in.

For $57.99, you can get 2 pounds of parts from this seller. The best part of this deal is the FREE SHIPPING. That along brings the price down quite a bit compared to other sellers. In fact it seems to be selling well, by the time I post this there wont be many left.