Cheapest and longest lasting are mutually exclusive terms when you're talking about tires. Don't cheap out. You'll be very disappointed. This car is still worth getting the best tires you can afford. Make sure the traction rating on the side wall is "A." This is a measure of wet breaking ability, and is a rough indication of how well the tire will perform on wet pavement. Also look at the treadwear number on the side wall. In theory, on the same car driven in the same conditions, a tire rated 500 will last exactly twice as long as a tire rated 250. The temperature rating on the side wall indicates how well the tire resists the effects of heat build up. Temperature should be at least a "B" but an "A" is better.