Disclaimer: I have only been diving for 1 year and only have 60-something dives under my belt, so take my thoughts with whatever size grain of salt you think is appropriate.
Dive Gear Express (aka DGX -
https://www.divegearexpress.com/) is an awesome vendor with a pretty much unbeatable return policy. I.e. they will basically take anything back, forever. Don't take my word for it. Go to their website and read their policy yourself. Call and talk to them. Also, they have as good prices as pretty much anyone.
The DGX600 light is awesome. And only $50, including a decent battery and a charger.
https://www.divegearexpress.com/dgx-600-handheld-light Get 2 for $100 and their Tenergy battery/charger set for $16 and you'll have everything you need for night diving - a light, a backup light, and enough batteries for both lights for 2 night dives (really, more than enough since you wouldn't normally use your backup light, so you wouldn't normally need to change the battery in it between dives). Note that DGX only claims 600 lumens output for these lights, but they are the same LED emitter as many other lights that claim 1000 lumen output. And that LED emitter is rated for just over 1000 lumens max raw output. In other words, the DGX rating is probably actually fairly accurate and most of those other lights that claim 1000 lumens and also use the CREE XM-L2 U2 LED are not actually delivering what they claim.
DGX also has pretty much everything you would possibly need for gear, except maybe wetsuits. They have a back plate and wing setup that would work for warm water diving and it's only $299.
https://www.divegearexpress.com/dgx-custom-singles-harness-backplate-wing-package Note that the wing in this package is identical to and made in the same factory as the Dive Rite Travel EXP wing. I have a Deep Sea Supply back plate and wing, myself, which has already been recommended. It is nice. But, I got mine used for $35. If I had to buy a new one, I would not spend $500 for one over the $300 rig from DGX. Actually, I also have a Hog 23# wing which DRiS just had on Black Friday sale for $150. If I had to buy a new rig for warm water, I would get another Hog 23# wing and a Hog back plate (were just selling for $60 for an aluminum plate) or DGX back plate. That is, if those items can still be had for something like those sale prices.
For regulators, Dive Right In Scuba has the Hollis DC3 + 212 regulator set on sale for $199. If you buy two of those, you'll have what you need (less a pressure gauge) plus a spare 1st stage left over (advantages already noted by tbone). And for $400!!
DC3-212 - Dive Right in Scuba Many people on here will poo poo this reg set, but it is a sealed diaphragm 1st stage and a fully adjustable, pneumatically balanced second stage. I have this exact set for my single tank diving and I have Dive Rite XT1 and XT2 reg sets for my double tank diving. My experience is that the Hollis regs breathe just slightly easier. Barely noticeable but enough for me to say that the Hollis work at least as well - for me, anyway. I've had my Hollis regs for almost exactly one year now and have somewhere roughly around 50 dives with them and I have no regrets on buying them whatsoever. If they had the option to route a Low Pressure hose out the bottom of the 1st stage, at that price, I would have bought another pair of them to use for doubles diving.
Note that if you get the Hollis regs from DRiS, they are DIN and you'll want to get a DIN-to-yoke adapter to be SURE you have no troubles using them in Bonaire or wherever you go. DGX sells those for $20.
https://www.divegearexpress.com/dgx-din-to-yoke-spin-on-adapter I have one but with 16 dives between Riviera Maya, Mexico, and Hawaii, I don't think I've ever had to use it. I haven't been a lot of places, but they've pretty much all had convertible (i.e. DIN or add an insert to the valve to use yoke) valves.
Regarding wetsuits, Coral Edge Adventures (
http://shop.coraledgeadventures.com/) has a bunch of different brands and models of wetsuits on closeout. I got my ScubaPro 3/2 EverFlex for $160 and SP EF 7/5 for $180. Both suits are higher end ScubaPro models that normally sell for quite a lot more but CEA has stock that is 2 or 3 years old (but still new) that they bought and are blowing out. They have Bare and WaterProof (both also top-notch brands for wetsuits) suits in some models for similar prices. They happen to be local to me, so I was able to go in and try suits on. I have bought a bunch of gear there and they have always done great by me.
Many people will say it's a dumb idea, but for a computer, I have an Oceanic Atom 3.0, with wireless air integration. I also have a Shearwater Petrel 2. I bought the Atom first and have no regrets on that, either. The wireless pressure gauge has worked flawlessly for me. I think it's a lot nicer than anything you'll get for $250 or less (meaning it is more money, but I have felt like it was worth it, to me). It has gauge mode and so even though I've moved on to starting to do tech diving, I still use the Atom as my backup for tech dives. And I definitely like the Atom better than the Petrel for recreational dives. My eyes are old and getting weak so I have gauge reader lenses in my masks. With those, I have never had any trouble reading the Atom. And it's a very nice size on my wrist. The Petrel is more like a brick and I find it often annoying - particularly any time I try to reach my arm into a hole or between things. The Petrel is the clear choice for using on deco dives. But, I definitely prefer the smaller, wristwatch size computer for recreational (i.e. no decompression stops) dives. LeisurePro lists the Atom 3.1 full kit at $900. I paid a lot less than that for mine, 1 year ago. If you are a little patient and shop around, you can probably do the same.
Lastly, a note about weight of gear and traveling. I already saw at least one comment having an eye towards getting lighter weight gear for traveling. Maybe you need that or maybe you don't. I packed my regs, stainless steel back plate, wing, mask, computers and 3mm full wetsuit in my carry-on suitcase when I flew to Mexico and to Hawaii. Being in my carry-on, the weight was irrelevant to the airlines. I only had to pack my fins and miscellaneous stuff in a checked back to have everything I needed in order to dive, with only renting my tanks. If you get an integrated BCD, you might not be able to fit all the same stuff in a carry-on bag, but even then it shouldn't make much difference to your weight limit for your checked luggage. All that said, I've seen some posts here that some airlines do actually weigh your carry-on bag. I've never seen that happen to anyone, and I don't know what airlines do it. Nor, for those airlines, do I know what their weight limit would be for a carry-on. If it's the same 50 # limit most use for checked bags, I think I'd still be okay - even with my 6# SS BP in there. The overall carry-on bag size just isn't THAT big.
Let's see:
$116 - DGX Lights plus batteries and chargers
$160 - 3/2 mm wetsuit
$400 - Hollis reg set
$300 - DGX back plate and wing
$145 - DR XT fins
$900 - Oceanic Atom 3.1 computer with wireless AI transmitter (your pressure gauge, so you don't need to buy a physical SPG) and data cable
$2021 (more or less) and you would be ready to dive (assuming you already have a mask)
Good luck with your shopping and your diving!