The simple answer is, Maybe.
Obviously the the real answer is more complicated. It also involves a few questions of it's own.
Q1 Are you trying to get a car sold, or moved? Then "YES". If you are trying to trade in a car the dealer will penalize your trade in value if the car does not have at least 4 32nds or tread and a matching set of tires. They'll give you less allowance on your trade in without even telling you that a $28 used tire would have allowed you another $200 in trade in value.
Q2 Are you turning in a lease? Then "YES". Again without 4 32nds of tread you are going be "fined" on your trade in. Read the fine print of your contract.
Q
3 Are you driving a salvage title car? Then "YES". Most salvage title cars are designated as such due to frame damage. This makes the tire track off, and they will eat tires. The car may be perfectly fine other than it's appetite for rubber. You should rotate your tires twice as often as normal and find a good supplier for used tires. In fact I once owned a Mercedes with this problem and I purchased the proper size used tires every time i came across them and kept my own supply. I highly recommend this if the size is 15 inches or smaller as those are much harder to find.
Q4 Is money tight? Then "YES" Many high quality used tires are available nearly everywhere. Make sure you are dealing with a reputable dealer who will install and warranty your tires. A little known secrete about the used tire market is that people who buy used tires generally buy a tire every 90 days. This is a much higher rate than new tires, so develop a relationship with a used tire dealer and stick with them, and they'll take real good care of you.
Q5 Are you looking for NEW or LIKE NEW tires for next to nothing? Then 'NO". two things about nearly new tires. #1 If it seems too good to be true then it's not. Most of the time that perfect tire has a broken belt, or pin holes in the side wall. #2 If they are like new then the dealer is going to command a premium for them, and most likely you could buy the same size in a cheaper brand for close to what you'll pay for them.
Q6 Have you damaged one or two of the tires you are now running? Then "YES". Many times matching your tires with used ones with similar tread wear is a great way to get the most out of the remaining tires on you car. Replacing one or two until you are ready to replace the set with new tires will maximize the value of your tires, and insure you get the most out of the tires as a whole.
The Bottom line is that used tires purchased from a dealer who stands behind their product can save you money in more ways than just the initial cost of the tires.
www.directusedtires.com
http://stores.ebay.com/Dudes-New-and-Used-Tires-and-Stuff?_rdc=1
http://www.mytiremonkey.com/Syndication/Order.aspx?AffiliateID=1522
http://www.tshirthell.com/store/clicks.php?partner=scottrents