Buttons

[theterbulence.livejournal.com]

So I'm making an art car and I need an absolute ton of buttons to coat the exterior of this car in (preferably blue, but other colors would be good too). My question is: where can i get cheap, lightweight, plastic buttons in some serious bulk without breaking the bank? I feel like I've been googling forever with no luck, so i figured I'd see if anyone here had any resources. Here's the car in question, so you get an idea of the area I'm planning to cover.