It's printed right on the side of the tire, and on a sticker in your door jamb. Someone might have a lead on some tires on sale.

The chain stores may also have a credit card with a 29% interest rate, if you're getting tax money in a month it won't sting too badly especially if you catch a sale.

If you're driving on bald tires and get in a wreck, you can get sued. Your insurance will pay for it but they won't like you so well after that and raise your rates in retribution.