I'd be very wary buying a second hand turntable from ebay, unless perhaps from a recognisable dealer and with a no quibbles returns policy. Lots of potential problems that are hard to prove/dispute....bearings problems (turntable and tonearm), warped platter, PSU issues and plenty more besides, not to mention all the service items which you might need to do on top (new belt, bearing oil, cartridge setup) which can be a bit of a specialist job. A lot of care need to be taken sending them through the post too.
Obviously, as with cameras, if the price is right it might be worth a punt, but you always need to do that with your eyes wide open.