You just need to be picky about which cheap tools you're willing to buy. I nearly live at Harbor Freight. That place is freakin' awesome. Every tool you can imagine is dirt cheap there.

Digital Multimeter - $10
snap ring pliers - $1.99
polishing wheels - $3.00 ea.
25 gallon air compressor - $129
etc...

Even teh good spark plug sockets will come apart if you're using them on hot plugs. But you're really not supposed to change your plugs while the engine's hot.