I haven't seen it mentioned as much recently but a while back some people used to recommend this site:
Car-Part.com--Used Auto Parts Market
Which lets you search parts available from various salvage yards. I've never bought anything through that site.
I think courtesyparts:
CourtesyParts | Genuine OEM Nissan Parts & Accessories
is popular on this forum.
I haven't really compared their prices with local dealer prices as much as I should. But I think once you factor in shipping costs, their cost might be close to just buying it from your local dealer.
If you can get the part number for the items that you're looking for, you may be able to plug it into Amazon to see if it comes up. You have to be careful because sometimes a bunch of third party results will come up. But for something like cup holders that might not matter as much.