echo what Pete has said.
Also worth noting: because of inferior electrical components used inside these routers, most of these "consumer" grade routers from D-Link, Linksys, Netgear, Trendnet, Buffalo, Asus, etc. are only good for approx. 2~3yrs before they start to misbehave and by then when that happens, there's nothing you can do (unless you know how to test/service/recertify them yourself and can do them cheep) but to either (a) dump them on craigslist as "gently used" and let the next gullible buyer takes on the bad router; or (b) trash them and get new ones and start all over again.
Also there's the possiblity of picking up a faulty unit just because the previous owner/seller may have attempted to load different firmware than the factory ones, or crashed/damaged the original one due to a firmware update gone wrong.
My advise:
(1) never buy used router unless you know how to test it or work on it if it needs repair.
(2) never trust any routers that have been "flashed"
(3) buy a brand-new unit whenever Tigerdirect, egghead, etc. have a sale and get one with 2 or 3 yrs warranty.
For wired, I go with Netgear DI-604/DI-614; for wireless, Linksys WRT54GL is my pick.
Q.