If you are having trouble with your tires wearing uneven then you either have worn suspension or steering parts or the front end or rear end is out of align. An easy way to detect this is to look at your tires. If the tread on the tires looks scrubbed or feathered  or just plain showing less tread on the inside or outside of your tires then you need work. The amount of work dollar wise can be vary greatly.I suggest taking it to a shop that can do any work required and also do the alignment. An unfortunate part of the auto repair industry is that too many people know too little about cars and a lot of auto mechanics use that to their advantage. I have heard the most outragious explanations for a car needing repairs. The only way around this is to find an honost shop or ask someone who knows something about cars. This web sight can help with knowing about cars.