Cheap?
H-F single speed version. On sale with a coupon usually you can get it down to about $10-$15 dollars.
If works. It's loud, single speed only, need to use the (or "a") hex key to put on and take off attachments, vibrates like crazy (will make your hands go numb after a while, YMMV there).
Want top of the line, smooth, variable speed, tool-less blade changes, and such? The latest Fein QSL-350 or the Bosch GOP40-30. Both use the new Star-Lock blade attachment system (can't use the 'old' style blades here), but if you don't have 'old' blades to use that doesn't really matter. The tool-less quick change of the blades is very nice IMNSHO.
The Bosch has soft-start, so the tool doesn't 'jump' out of your hands when you switch it on (nice feature), and LED light in the nose (nice feature), and variable speed (on low, the machine is quiet enough that you don't even need hearing protection and someone in the next room might not even notice the noise). Go for the GOP40-30C kit, and you get a decent hard case and some more blades along with the OMT.
The Fein is nice, but a bit more money than the already higher-end priced Bosch.
Blades? Bosch. Other companies may make some decent blades, but I don't think I have ever gotten a 'bad' Bosch blade (in several tool types).
Tip, make sure to use the 'right' blade for the task at hand! Using a 'wood' blade to cut (or try to cut) metal (like a nail inside the wood) ruins the blade almost instantly.