If the track you've seen on eBay looks more like "normal" track (rails and sleepers), rather than the all-in-one moulded track and roadbed of the Playmobil track, then chances are that it is most probably some of the Chinese-made Newqida (sometimes also sold under the "Train" brand). The Newqida stuff is OK for the price, it is usually moulded in brown plastic, its biggest disadvantage is the very small number of different pieces available - basically straights, Radius 1 (4 foot diameter circle) curves and left and right hand Radius 1 points. If you're planning just a small layout with short (4 or 6 wheel) locos and short rolling stock, then it's quite useable, but for anything more extensive - and for larger locos and rolling stock where you will want large curve radii and larger radius points - it's not much use.
There are a few other plastic track makes out there, including other Chinese made stuff sold under various names like New Ray, New Bright etc, and LGB themselves made some black plastic track a long time ago for their early battery-powered starter sets (do beware of that - the plastic gets VERY brittle with age), but as Mike says above most of them are not compatible with the connectors of the others - which is a problem because the connectors are usually moulded as an integral part of the rail-end and can't easily be substituted; they also all suffer the same fundamental problem as the Newqida, in that you can only get tight Radius 1 curves and points.
Personally, even if you're running battery only, I would invest in some well-used second-hand brass track - you won't be worrying about electrical continuity or clean rails, but the track itself will last almost forever.....
Jon.
thanks 
