I need help finding a new rear axle
 

The only rear axle I can find new is on gmdirect.com or something like that and it's 800 dollars, the inner parts of my tires are waaaay worn down while the outer parts look almost new, I can't find aftermarket at all and only 800 for the oem, I'd really appreciate the help, also if it matters my car has been lowered

Junkyard salvage if you don't want to pay brand new. Google your nearby wreckers they usually have inventories of vehicles in the scrap yards.

are you talking about a rear axle beam?

Yeah the beam seems to be bowed in, also can a normal mechanic put it in right or is there some specific way or does it need to be aligned somehow? I'm just not sure and I wanna double check that I'm not wasting money throwing parts at it

It's attached by 6 or 8 bolts iirc (other things have to be removed also) but it's pretty straight forward, would recommend an alignment after.

I took it to be aligned at firestone and they told me it's a solid beam so it can't be aligned so what do you mean

I Know when I had my first ss I was in an accident where the rear axle beam was out 1 degree. The body shop found it out after they thought everything was fixed. So I'd say a four wheel alignment would be able to tell if it's out or not.