Which baby items are okay to get used?

Sarah
One blessing/curse I've noticed about pregnancy is a lot of people come out of the woodwork to give you their old baby stuff which is AWESOME because it's all so expensive and temporary. As a first time mom (due 10/21) I'm having a lot of offers for everything from bottles, toys, pack n plays, car seats, changing pads, diaper genies and potties. But I also have a registry that I've worked hard to research and narrow down. What kind of products are great to nab used and what you stay away from used?? Thanks in advance!