You mean what are commonly called "Ramcharger wheels" ?
I don't know the part #, but 15x8, 4.5 BS, 5 on 4.5 sounds like them.
I've bought several over the last 40 years, and they've always been around $80-$100 each in decent but not mint condition - basically needing blasting & painting, but straight & usable.
The aftermarket, I think, kept the used prices pretty steady; but now they're probably 50% higher.
I've bought new aftermarket steel wheels (Magnums) that I had to return for runout and/or crookedly-welded centers.

Hubcaps - if they're the later generic type - are priced all over the place; look at Ebay prices.
Stainless caps are better than the later aluminum.