If you've got a keyboard, check if it has USB or MIDI ports. If it does, you're in luck.

If you've got both, USB is simpler. Get a driver from the keyboard company's site and connect it with a USB cable. (Check if the driver is compatible! For example, Casio USB doesn't work on Macs.)

If you're stuck with just a MIDI port, you can find a good MIDI-to-USB adapter for around $30. Price and brand don't make a difference. If it's going to work, it'll work 100%.

(One caveat: DO NOT BUY the M-Audio MidiSport Uno adapter. I've heard from more people having trouble with that adapter than all the other problem reports combined! Save yourself some trouble.)

Otherwise, I've tried this adapter on lots of computers and keyboards. It worked every time and I didn't even need the driver. It's got nice long cables, too.

	Nearly the most affordable way to start playing the game. 61-keys, no built-in speakers, but only $130.
(Otherwise, it's time to update this list again now that another year of products has come and gone. I'll have some new recommendations up by mid-January.)