Rainbow SE vacuum cleaner, $5.

The Rainbow vacuum cleaner is a unique machine in that instead of a filter bag, it uses water to trap the dirt. A pot in the lower part of the unit is filled with water, and the water/dirt mix is emptied after each use. Rainbow machines cost a lot to buy new, and they have a very powerful following of loyal customers. These two elements translate to a very strong market on eBay. So learn a little about them and make money!

Check out the picture below and memorize it, because you will be seeing these machines around. The Rainbow vacuum cleaner, with its weird bullet shape and unusual woodgrain pattern, looks so bizarre that it'll literally reach out and grab you.

I'm not one who finds it necessary to plug in and test every vacuum cleaner I find, simply because I've found it quite rare for a vacuum to fail because of the motor. But I have encountered several Rainbow vacuum cleaners with bad motor bearings, very likely caused by water getting into the motor. Interestingly, you can even buy replacement motors for Rainbow vacuums. And yes, people on eBay will pay you well for them, too. So you may as well know what they look like in case you see one.

My advice to you is, unless you're only paying a few dollars for a particular vacuum, always run the machine before you buy it! Make sure that the motor not only works, but that it runs smoothly and without any unusual noises.

Another note of caution - there's an older model of Rainbow called the 'D3,' which looks similar to this SE model, and sports the same hip woodgrain finish, but doesn't command near the same price as the SE. Learn what it looks like so you'll know it when you see it.

You may have noticed the bad news about the unit in this example - I didn't get any of the attachments except for the power head. The good news, though, is that the power head attachment alone (the part with the motor and beater bar seen in the pic) can sell for over $50 used on eBay.

This vacuum sold for $167.50 on eBay.

Photo of the Rainboe SE canister vacuum cleaner