It all depends on what you want.
If you see something that you would like then THINK HARD about the maximum you are prepared to pay for it - and STICK to it. Too many people on Ebay 'chase' items as the price rises above what they wanted to pay. As a result they end up with a bad deal.
If you think that some 'bid rigging' has been going on then report your suspicions to Ebay. People should not get away with such behaviour.
I've noticed in recent months that some sellers are giving ambiguous descriptions with or without fuzzy photos and failing to mention that an item is a copy - not an original.
Check the sellers feedback and see what other people think of them - this has been sufficient to prevent me from bidding for a few items.
If you have any questions then email the seller - and be quite blunt, but polite, with the wording of the question - before the auction ends.
If in doubt - Leave it.
I've been on Ebay for about 18 months and built up a feedback rating of 117 but I still treat most auctions with suspicion.
Good luck and Happy hunting. Be carefull out there.