Roseville used to give amazing discounts (20%), then covid knocked them to 15, then down to 10 and last I was told by them, no discounts. That said, I still support them because they've been really good to a lot of people including me. I've spent thousands on sheet metal for my 70 Cuda, all through them because of either discounts, or service, usually both. They typically drop ship, so shipping is often the same as AMD.
The only time I had a problem was when I was told (by them) they will buy as many, if not all of something like shaker hoods when they become available. That killed a sale for me because they don't get nearly the good shipping rates AMD does due to volume. so I had to wait for the next run. That said, they drop shipped mine before buying them all of for themselves last time.
I also bought a floor from a local resto shop that ordered a lot of AMD stuff. They were able to combine shipping with somepone their own order and we shared that cost so that's an option if you can find someone willing to do that.