Replacing front tires

Hi.
I have an '89 Olds car with 4 Goodyear Aquatred tires on it.
I need to replace the front pair of tires as the car will not pass
state inspection because of tread depth. I want to just replace the
front tires as the rear tires are still in good shape, tread-wise.
Question I have is that the tread toward the inside of the tire on both
the front tires is worn down more than the outside part of the tread.
What does this signify and what do I need to have adjusted when I bring
the car in to replace the tires?
Also, I do not want to spend the extra $ on new Aquatreds so what is a
decent tire/brand that I can put on the front axle given the rear axle
still has Aquatreds?

Thanks.
Walter