phonograph fun

I do a lot of digging through old records for any interesting samples I can find. A lot of times I go to second hand shops and such where there is no turntable set up to review material before you buy.
I've heard about these little portable phonograph players that are kind of like little toy cars with a needle on the underside and a built in speaker on top. Apparently, you can set this on the record and it will walk around the track letting you hear it. If there's another digger in the house who knows of these things, what they're called, and where to find one: hook me up with the info.
Gracias,
Progress