If your tracking is out, and wearing your tyres unevenly, get it reset asap. It will cost a lot less than buying a pair of front tyres. Get a price from your local tyre centre, i.e. Halfords, Kwik-Fit, etc.
Havn't had it done recently but it is quite expensive because of the time it takes.
Last time I think I paid about £30 at a specialist tyre centre. Was a while ago though.