Thanks for the welcome!
We're playing quite a variety of tunes: Stone Temple Pilots, Tom Petty, Pearl Jam, Red Hot Chili Peppers, Bob Seger, Grand Funk Railroad, Beatles, Santana, and others. Some rock from the 70s, 80's, 90s. We also just do some Blues jamming where we take turns playing a lead progression.
I played a lot of that same type of mix though my group was two guitars, keys, drums and me. I'd suggest getting separate head and cabs so you can upgrade as needed without having to re-buy another full combo to get either better speakers or a more powerful amp.
First things first, a single 115 combo is NOT going to cut it for what you are describing. Been there, done that, was totally buried!
If you're going to look at combos, don't look at any that are rated below 500-watts or you'll end up finding yourself looking at the 500-watt ones soon after you've already bought the 200 or 300-watt ones because you'll need it for the larger venues. Most (not all) combos have internal speakers that are rated at 8 ohms and amps that have a minimum ohm load of 4 ohms. At 8 ohms, those amps put out half or slightly more than half of what they put out at 4 ohms.
For example the Fender Rumble 500 is rated at 500-watts rms into 4 ohms. But it doesn't deliver 500-watts as-is. It's 210 speaker configuration is 8 ohms. Instead of getting 500-watts out of that your are getting 300-watts rms into its internal speakers. That's actually pretty good, some combos would put out 250 to 275 watts into 8 ohms. Depending on how loud your guitarists are, that 300 watts is usually enough for small and medium-sized venues. But to get all 500-watts from that amp in the combo, you have to add another Rumble 8 ohm 210 cab to it. And that's not a bad set-up. If you are running 500-watts into a 410 configuration (two 210 cabs) you should be able to play most venues without FOH support.
There's a saying that goes around TB, which is a bit of a classic and very true, "High Power, Lightweight, inexpensive - choose any two." Unless you find some really crazy deals on used gear, you are not going to get all of that between $500 and $800. By the time you add the second cabinet to that Rumble, you will have much more than 35-lbs all together. The combo is 36½-lbs by itself and the second cabinet is another 39-lbs. That's really not bad though because the combo will work by itself for small and most medium-sized clubs though you will definitely want the extra power and speakers for the larger medium-sized and all the large venues.
As far as weight goes, the amps themselves are not the problem. With class D amps, you can get 800-watt amps such as the DNA-800 (I am a DNA Endorsing Artist), that weigh under 5-lbs. DNA-800 is 4.8-lbs. Most of the major Bass brands also have 800-watt Class D amps and like the DNA one, most of those are ~$799 new (always cheeper for used gear of course). But the weight of the speakers is going to add a lot of weight. It takes a big magnet to produce those low bass frequencies and a very solidly built cabinet to keep from shaking apart in a few years from all that vibration.
There's also a very nice 500-watt Eden Class D amp, the TN501, that weighs 5.3-lbs. I have its younger brother the TN226 which is a 226-watt amp. I specifically use it for a small venue that we used to play a lot. I pair that with a single Eden EX-112 cab and it was enough for that venue. I use my big Eden amp with my other cabs for other venues...wish I had purchased the TN501 instead of the TN226, but bought it used from a friend and got a good price on it.
It has the same warm Eden sound that my big Eden hybrid amp has even though it doesn't have a hybrid preamp. If I'd expected to use it more places, I would have bought the 500-watt version and 8 ohm speakers instead of 4 ohm. I bought the 4 ohm because I was only going to use it at that one place but the first night I played through it, I liked it so much I bought a second one. I used the two EX-112 cabs with my big Eden amp for medium-sized venues for about a year until I bought my DNS-210.
I personally use a DNS-210 cab (by DNA) for ALL of my indoor venues now and reserve my DNS-410 for outdoor and festival venues. But my DNS-210 cab is pretty unusual. It handles 700-watts rms, both thermally and mechanically, and it will produce a maximum SPL of 134db. That's beyond the threshold of pain and causes immediate hearing damage though, so you wouldn't want to be anywhere near it at those levels. And the older Eden WT500/800 amp I have bridges into 8 ohms at 800-watts. So if I run my amp bridged at 800-watts into it most of the way up, I could hit that level if I needed to. But I rarely run my master on my 800-watt amp above 10 o'clock. I don't want to be anywhere near that amp/speaker set up with it hitting 134db.
That DNS-210 weighs 52-lbs which isn't as heavy as the Eden 210 cabs that David designed, but it's still not very light, and it's also not very cheap. Street price runs around $900 - $969 new although you can sometimes find used around $600. A DNA-800 amp and DNS-210 cab together would weigh just under 57-lbs and handles all my indoor venues - small, medium, and large. It would also run you around $1,700 new. You might be able to put them together a used set for a little over $1100 or $1200 but that's more than a little bit over your budget.
So realistically for the near future, I'd suggest you look at class D amps of 500-watts or more along with a 210 cabinet. Add either a 210 cabinet or a 410 cabinet down the road. That way a 210 cab will cover your small and medium venues, the 410 cabinet with your 500-watt amp will cover the large venues. If you start playing outdoor venues or festivals, then you'll probably need to go up to an 800-watt amp, but with both a 210 and a 410 cab making a defacto 610 speaker system with an 800-watt amp driving it, you should be fine.