Absolutely, research the price. Figure out what it is worth to you, then bid accordingly. If it sells for $350 at Best Buy, and $300 at buy.com, and the lowest price on www.froogle.com is $280, then you have some basis for what the item costs new, at a dealer. Then you have to take into account the risk of buying from the given seller, the apparent condition of the item, shipping costs, etc, and then come up with a maximum price that you are comfortable with. Then bid that amount.
Note that the above is all about price, and you. No internet psychology needed.
If somebody else values it more than you, they will win. That’s OK. You can’t always win (unless you are Bill Gates).