Cheap parts for beater

[Kougar]

My DD is basically dangerous in its current state. Obviouslly, I need to change this. Thing is, i'm hella-poor and need to spend my money incredibly wisely. It needs tires, shocks, a caliper, and a catback/02 sensor weld.

What's most important here? I only plan on getting it through spring. I was thinking tires and brakes, and exhuast if i got any left over.

Anyhoo, where can I find some CHEAP 14" tires? They can even be slightly used for all I care.

As for the exhaust, I plan on buying a universal 'normal' muffler ($20 at checker) then having an exhaust shop crushbend a pipe, connect it to my cat, then weld muffler on (and weld 02 sensor back on).

Brake caliper is $50 reman at checker...good idea?

Overall, I think I can do brakes, exhaust, and tires IF and only if i find the tires cheap enough, so it all hinges on that.