If you haven't had a wheel alignment done within 50,000 to 100,000 miles then it would probably be a good idea to get a wheel alignment done before you get new tires.
If you don't get a wheel alignment and get new tires then your new tires may wear out faster and unevenly.
Look at your tires and see if they are wearing evenly or unevenly.
If the tires are wearing out unevenly then you should get a wheel alignment before getting new tires installed.
A wheel alignment for one axle is around $75.00 to $100.00 depending on the vehicle.
So it's less cost for a wheel alignment than usually what it costs for one or two tires.