This is YMMV ~ I do not know if eBay offers this to everyone or a subset of their registered users. Good until Sunday night (5/7/17 at 11:59pm pacific), you earn 8% on $50+ items purchased during this promotional period. Some exclusions apply as usual and the maximum rewards you can earn is $100 per transaction, and $500 during the promotional period.
eBay could do a better job describing these promotions in the emails since they do not clearly outline the difference between a “$50+ item” and a “$50+ purchase”. The former is clear that it has to be reached with a single item. The latter is confusing since eBay now has a proper shopping cart and you can reach $50+ with 100 $0.50 widgets. I’m assuming this promotion is for the former (individual items priced $50+ individually).
A good place to look for ideas are the eBay Deals along with the Trending Deals (shows only 100 trending deals, less overwhelming to look at than their main deals page). There’s also a dedicated search box there that searches only the Deals, not everything else on eBay.