I have used ebay a bit for various things, but it is definitely a case of "caveat emptor", you have to take things on trust. In the last 6 months I've bought
DeWalt 621 Router (used)
Ryobi 601 router (used - bargain)
Woodcraft Router table (used)
Elu ETS3151 table saw
Nutools thicknesser (new)
A0 drawing board (used)
plus other bits & pieces
I have never been disappointed with what I've bought, but it does pay to do your homework first to find out how much the tool costs new etc. Also factor in delivery costs or petrol costs if collecting.
A few months back, I nearly bought an Eumenia radial arm saw (but was outbid). The next week, the same model was on offer at Axminster for less than my bid

Lucky escape.