One of the most popular tools Sears sells for under $50 is the 2 gal on Cordless Shop Vac at Sears.com

In reality the most popular should be the 19.2 C3 Cordless Wet/Dry Vac.  This vac has a lot of features for the price, comes with all the attachments, and is cordless for about the same price.

Listed on Sears.com as Craftsman C3 Wet/Dry Vac

Features:

Good Suction
Uses 19.2 volt batteries. Will use the 19.2 v diehard NiCads, small lithiums and the high capacity lithium-ions
Doubles as a 100 mph blower.
Comes with a good assortment of tools including, extension wand, hose, wide nozzle with squeegee, Crevice tool, Car Nozzle, Floor Brush and removable tool storage belt.
It also comes with three dry filters and a foam sleeve for wet pickup.

Everything fits right on the vac using the tool belt. It is lightweight and has plenty of power to clean your car, stairs or pickup wet spills.

It even has a drain plug for emptying liquids.

Here is a quick video showing the Model 17598 in action.  Sears sent this one to me to try out.  

Summary:

If you have 19.2 volt C3 tools this is a must have to compliment your set.  It is strong, lightweight and easy to use.  I like it especially well for stairs and vehicles.

Order it here: at Sears.com Pick it up at your nearest Sears or have it shipped right to your home!