318 pulley mistake, need the correct size.

The measurements are pretty close to what I need, but the price is too much. With shipping, fees and taxes I'll be spending around $70 and then I still need to spend time cleaning and painting it. I don't know if the seller will accept 25 - 35 dollars, I'll try.
Made an offer of 40 dollars and it was accepted, I think it's fair enough considering it's on ebay. This pulley should work by my math.