They're based off contracts dude. Everyone is going to be slightly different depending on your demands, and their demands. A small, local label won't do much for you in the way of advertising or promoting, in fact, most major labels won't promote you either, except for your albums that you write for them. In terms of shows/concerts, the promotion is on you and your promoter.... although, the label will have connections for you to other bands, as well as getting you hooked up with better shows... and that's if they're a legit label.
Now, some major labels may provide you with a promoter if that's in your contract.
Most small companies have no money to really provide you with anything, except with knowledge of the industry, and possibly a connection to a distribution company, that will help distribute your album. A record label will not provide you shows, unless they are doing a special show/tour where they are trying to promote your band and several other of there bands record release at the same time.
How much do bands make off there albums? Probably enough to recooperate the costs of making the album. Label will probably take more like 95% of the earnings, especially if they are the ones putting up money for studio time, a producer, etc. Most will tell you they will take 100% until they feel they have covered the expenses involved in your album.... although, they can probably claim a lot of expenses went into the your record and promotion of the record, even if it doesn' directly apply to your band. I've heard of some labels taking the money to produce other bands, and saying that it affected your band. I mean, this is what they do... they produce records, right? If they pay for your time in the studio, then that means they had to get money from another bands success.
It will/should be in your contract how much they are willing to put up, say, $15000 for studio time. Anything over that, and it's coming out of your pocket. If they provide you a producer, then they may tell the producer what they want the album to sound like. They can tell you to re-write a song, because they're the ones paying for it. You're working for them, and in there minds, they want it to sound a certain way, so they can make money... because, after all, it is a business, and they need to make money too. They can't just leave it up to the band to make an album and "pray" that it tunes out good. They can give you guidelines on what they think will sell. If you don't like it, then you quit and break the contract. That's up to you. As time goes on, if your band gets famous and makes them gobs of money, you'll have to sign a new contract, where you'll have more power to produce the album, hopefully.
You make your money off touring and merchandise. They make there money off trying to sell you album. You want them to sell your album, because that gets your name out, which in turn, will get you bigger shows and more money for merchandise, etc.
If you have someone interested in you, you should try and contact the other bands on the label to see if they are legit and what the label did for them, if anything.
Truth be told, most labels won't do anything for you. They will only take a chance on bands who are already touring and selling merchandise, and who have already made a demo album, or even full length album. They're no longer interested in wasting money on project bands that end up quitting in 2 years or before the end of the contract. They go after the bands who look like that they are already a pollished band. They they take the album, market it to radio/satellite radio, internet, myspace, facebook, whatever. They will have connections to other bands, and get you hooked up with bigger shows, with better bands, which will have a higher turnout in the audience, hence, more people will see you, then possibly buy your t-shirts or albums. The big labels already have huge connections... the smaller ones, you never know, so ask the other bands what they think of the lable.