Welcome. A few observations.
1.) Figure out what kind of diving you want to do. A tropical diver who's not very cold sensitive may be happy in a 3-mm full or shorty wetsuit. Someone doing some quarry diving spending time in water in the 60's may want a 'dual purpose' 5-mm wetsuit - tolerable in the tropics, fine in the quarry beneath that first thermocline.
2.) You may want to buy yourself things that need to fit. A mask with little or no leakage is a wonderful find, and cost doesn't necessarily determine fit. I'm a tough fit, and my mask was pretty cheap. Scuba boots and fins need to fit, especially if you have usually big feet like I do. A wetsuit especially needs to fit.
3.) If you dive locally, you may or may not want to buy a tank, and then there's the steel vs. aluminum and how many cubic feet debate. Be mindful you'll need to pay for periodic hydro. and viz. on a tank. May not be worth it. When you make dive trips abroad, tanks and weights are likely to be provided.
4.) A dive computer is nice to know how to use. Unlike a BCD or regulator, the interface will vary widely against competitors. Console, wrist puck or watch style? Air integrated or not? Capable of downloading dives to your computer or not? Intuitive interface or one more like a typical wrist watch?
If you are foot-heavy like many divers, fins that aren't negatively buoyant are a good start. I like my 2XL Deep 6 Eddy fins, which are slightly positively buoyant and have big fin pockets. Don't expect to find them used, but the prices are good (and they come with spring straps).
If you guy a regulator 2nd hand, you'll likely want to get it serviced before you use it. You'll want a brand that a local dive shop services, by the way. I like my Atomic Aquatics B2, but I've found getting it serviced on Caribbean trips when things came up...was more difficult. I think ScubaPro is easier to find servicing abroad for, when something goes wrong.
Most divers dive jacket-style BCDs. On this forum, a lot of people like back plate/wing setups. Either works; be aware there are options (and there are other options, like rear inflate, the ScubaPro Hydros, etc...).
If you really want to know what people here think, post asking about the gear before you buy it. If you buy and then post asking if you got a good deal, it's a bit late.