Try the Search function, or the newbie links sticky. There is a lot of info that has been already covered on this forum that will answer many of your questions.
To get you started, though:
1. It's a negotiation - you both set the price depending on what you both agree to.
2. How much you get paid is completely dependent on your situation. If you are playing originals, expect to play for nothing, or even be required to pre-sell tickets or pay-to-play if you are in a high-supply market (LA, etc). If you are playing covers, you might expect anywhere from free beer to a few hundred for a bar gig, up to several thousand for a wedding or private party.
3. The same goes for out-of-town gigs as in-town gigs: it completely depends on what you're worth. An out-of-town bar doesn't care that you are not local and they are not going to pay you extra just because you had to drive to the gig. They will, however, pay you for bringing in people who spend money at the bar. Whether this is in your own town or another town is pretty much irrelevant. As far as calling up venues, don't ask to play - offer to play. You are the one providing the service. If you ask to play, they will say, "Sure; come on down. We'll give you 30 minutes opening for such-and-such act if you guarantee that you can bring 50 people. Tell you what, we'll even throw in two beers apiece for the guys in your band. See you next Friday!" If you offer to play ( a service), they will want to know 1) what's in it for them and 2) how much it's gonna cost. You are soliciting business - you will need some credibility and probably a demo or promokit, with some information about past shows you have played and your draw (how many people you can bring), if you want to get paid.
4. As far as determining prices, there are many factors. How many people you can bring is by far the most important. They will also want to know the age group of the people (if all of your fans are high-school age, and they are a bar, they will lose money on labor giving out free refills on $1 sodas all night). If your fans are college-age binge drinkers, you can charge a lot more
Experience doesn't count for much - fan base size does, but a bar will usually see the value in booking a band that has some idea of what they're doing (as far as running a show - setting up, tearing down, putting on a good show, engaging the crowd, promoting the show well to get the most people there, etc). It really boils down to professionalism more than experience. You can have a band that's been together for 15 years and still doesn't know what they're doing, but you can also have a band of 21-year-olds who have been together for 3 months and know how to do a good job promoting and playing a show that commands higher pay.
Hope this helps,
