I've yet to search much on eBay, one of the stores in Sweden has had a decent influx of used copies so far. But others seemed to get the same idea so might have to branch out.

I saw how much this hobby/game got more popular (from 3 million players worldwide to 50 million so 700%+ apparently) it's getting more difficult to find some and prices are skyrocketing for some. It's spicy-ing the hunt so far, but I'm glad if it means more interactions and opportunities to play D&D

Very true, I'm so thankful that there are always some local bookstores and gaming ones (like Micromania-Zing and Philibert) which sometimes give discounts for used & refunded items. ✨🙏 Last month, I bought a Xanathar's Guide to Everything for around 10€ instead of 39,99€.