Is it safe to buy used 32GB RAM kits from eBay?

Yes, but only from sellers with good ratings and return policies. RAM is one of the safer components to buy used because it either works or it doesn’t. Stick to sellers with 98%+ positive feedback who accept returns, and make sure the kit matches your motherboard’s supported speed and generation. For DDR4, the savings are big and reliability is solid; for DDR5, lean new unless the deal is insane with a return window.