That one thick washer with the pin through it may not be a standard part. They may have to get it made. For what it is, & coming from an OEM, the price
seems OK to me.
My second choice option would be to have a thinner washer with pin hole made up by a local machine shop & then put a standard-thickness (thin) hardened washer on top of it. If the total thickness of the two new parts
is the same as the original, then this should work fine & let you use all standard (inexpensive) parts in the future. I would make the new pinned washer out of plain mild steel
, like 1018 or lead-loy like 12L14. That is, assuming that there is enough room in the assembly to allow you the space to fit the extra washer.
Around here, I could get that part made out of mild steel
for about $25. Having it hardened & ground, would probably jack up the total price to over $100 for a 1-off. If someone (like an OEM) were getting 50 of them made, the price would come down considerably.