I have about 200 dives.
My recommendation for new divers is buy a computer, a mask, and fins. Rent everything else for your first few trips. You will learn what you like and then can decide if you want to buy the rest.
You can walk into a scuba shop and walk out with a hefty bill so be careful. Mask and fins will probably run you $200 total for decent stuff. You can get a good computer for under 500, even cheaper on EBay. If you buy used, take it to a scuba shop that can change the battery (if it’s not new enough to be rechargeable) and pressure test it.
Where I dive the most, Cozumel, you’ll pay around 90-130 per 2 tank boat dive. It varies a lot from place to place, for example Hawai’i was almost twice as expensive.
Edit: sorry was typing fast at dinner during a break, fixed the 2 tank dive price in Coz.
scuba board dot com is also a great forum to get info from.
Hope that helps!
edit: To clarify what I meant about scuba shops, they are in the business of selling. They are going to try to sell you really good (read: expensive) stuff. You don't need to have $3K of kit to SCUBA. Don't let them pressure you. The good ones won't, but I have unfortunately seen some that will.