I'll add my ten cents.
Get a low-profile mask. They're easier to clear, and you'll have better peripheral vision, which makes life easier in general. My mask is super low-profile (it almost touches my eyelashes), and I think it's great. You could get a used mask if it's still in practically new condition. If the skirt or strap is starting to look yellow or feel tough instead of soft, it's probably no good. If the skirt has any tiny tears, forget about it, because it'll leak. If you get a mask and it keeps leaking, get another one ASAP, because a persistently leaky mask can ruin a dive.
We do use our snorkels, because in the ocean the waves splash a lot, and salt water isn't nice to have in your mouth. So as soon as the regulator comes out, the snorkel goes in, unless we have to talk about something. I occasionally use the snorkel in the lake to see what's below me on a surface swim, but not as often as I use it in the ocean. I prefer a snorkel with a wide bore (wide tube) for easier breathing, and splash guard at the top. The purge valve on mine causes more problems than it solves. I wouldn't bother with a used snorkel, because it could have fungus or some other nasty in it, and they're cheap. I think ours were $25 or so.
We initially bought booties that zip up, but we're changing over to the kind that just pull up, because the zippers have a tendency to unzip, and the velcro zipper keeper quickly loses its ability to stay put. You might want to choose your booties before you choose your fins, to make sure the fins fit properly with the booties on. I wouldn't bother with used booties, because they could have fungus or some other nasty in them, and they're cheap.
We have Mares Avanti Quattro Pro fins, which are expensive but nice. We see a lot of seasoned divers with those, and we have zero complaints. The open heel design is nice, because you can use the fins with different types of booties and with spring straps someday. Fins are something you can buy used. Even if they look scuffed up, they're probably fine, as long as the fin still has its proper shape, and it doesn't have any cracks in it. Ours already look pretty scraped up after 20 dives.