Many baby monitors have infra-red LEDs and see passably well in the dark, so you could set one up in your garage and then sit quietly inside watching the monitor with the baby monitor volume turned way up so you don't have to stare at it all night. Someone ends up in your garage, walk in and if he's facing you, shoot him. If there are multiple people, shoot anyone facing you while shouting to your imaginary backup to "get the other guy", to make sure anyone you don't shoot will end up running.
If you want to use "bait", leave your garage door open about a foot.
Use a shotgun to make sure you get some hits. Wal-Mart often has a cheap Mossberg 12-ga pump on sale for under $150, and shotgun shells seem to be the only ammo still on the shelves.