Like some of us you may want to attach extra parts to your Transformers and Rare Earth magnets are pretty useful. RadioShack has a pack of two for around $3. However I found a MUCH more plentiful supply in MagnaWheels Street Racers. These are little car-kits by Mega Bloks brand 'Magnetix'. I picked up the Dodge Viper for a blower/pipes for my Hot Rod custom and was thinking what I could do with the leftover car. One pair of clippers and five minutes later I had SIXTEEN rare earth magnets. Eight thin and eight stocky. They're round and about the same diameter as the radioshack magnets. The MagnaWheels are $8.99-$10 putting the magnets at sixy cents each or so. They're more powerful as well! So the next time you need some magnets, snag a MagnaWheels Street Racer kit and cack the magnets out of that. You'll even end up with rubber tires, engines, and extra stuff to use on your customs to boot!
Here's a pic of the leftover magnets. I used a bunch of the flat ones in my last customs so the stack isn't as big as it was. All that came from the one viper kit there!