Yeah, Curlyguy and Americorp's advice is good. You need to set clear boundaries for missing classes. Students, unintentionally or not, will be thinking of their own time and convenience, not yours. You need to ask for payment in advance and set up a system for cancelling classes, ideally 24 hours notice or they lose it.
In terms of money, well, that depends on your experience, if you have a lot of experience and a teaching qualification and you're a native speaker, you can generally ask between $15-20 an hour. If you don't have a lot of experience, or a qualification, you'll be looking more at around the $10-15 an hour. If you go to the student's workplace or home means you can ask for more. As you're going it alone, you're probably better to start off at the lower end and attract students by word of mouth. You can really only start asking for more once you've got a reputation, because wherever you advertise there's bound to be someone offering classes for less.
Once you get over the $20-25 an hour barrier, you'll be competing with the language schools, who offer all sorts of materials and support with their package and usually the students aren't paying, but rather the companies they work for. Often the teachers at these schools are just foreigners staying in Lima for a few months with few qualifications, so they're not always the best teachers, but the advantage of the language schools is if the students don't like their teacher, they usually just ask for another.