every time i see threads like this, i'm tempted to post this. but i usually refrain. usually....
the thing about bar gigs is that there is no money in them and there never will be. it's not because the bar owners are cheap, although many are. it's not because the bands are cheap, although some are that as well. it's just simple economics.
the only reason a bar band gets paid is if they sell drinks. so, say the bar band gets paid 500 bucks. in order for this to make sense for the bar owner, the band has to see to it that there is a at least 500 EXTRA dollars in drink profits over what they would sell just playing CDs. That's not 500 Gross sales, That's NET after all of the owner's fixed costs, some of which go UP just because there's more people in the bar [another bartender, bouncer, ETC.]
Now, i'm not, not will i ever be, a bar owner. But i'm betting that you need to see a WHOLE lot of 5 dollar beers to cover that difference. I don't know, maybe 200 or so? at least? probably more? Someone with more experience in this area can chime in. Still, it takes a LOT of booze to cover the band at 500 bucks. now out of that the band needs to get some money for their troubles [split 4-5 ways] and the sound guy needs some cash. Guess what? nobody is going home with a pocketful of money.
The bad part about this little issue is that scaling up or down doesn't really mitigate the problem. Smaller bar=less PA/band provided sound=lower costs but less extra drinks sold=less money. Bigger bar=More PA=Higher costs and more drinks sold=more money but split more ways. You can find situations where you can shade this equation a bit more to your advantage, but you're never gonna win the game. The reason for this boils down to one simple fact. You, the band, and the bar owner and the bar's employees are prying your money from the hands of hard-working regular joes and josephines and they are not gonna give it up easily. First rule of making money is make sure you're getting paid by someone that is NOT spending their own money.
Bar gigs are for people who like hanging out in bars and making loud noises. they aren't for making money and they never will be. They're for losing money. the only variable is how much you're gonna lose. I don't mean that to be condescending or anything remotely like it. it just is what is.
If you want to make money doing sound, let go of doing sound for cool bands. even at the top of the game there's no money in it. Do sound for boring talking heads from companies that have accounting departments that are paying you the COMPANY's money. Sometimes those gigs have cool bands too. But either way the checks always clear.
If you want to do this as a hobby, go for it. nothing wrong with that. But if that's what you're doing, don't stress over how much money you're making. It's just not worth fretting over....