As long as there's no intent to deceive (e.g. by saying that it's for charity), anyone is free to organize any form of competition they like and keep the profits. The only proviso is that the competition must be a test of skill (e.g. a quiz) rather than solely or mainly a game of chance (e.g. a raffle or a game of poker).
Television companies make vast amounts of money from 'quizzes' where they ask incredibly simple questions to get lots of people to phone in (at premium rates). They have no special rights within the law; anyone is free to organise similar 'competitions' and keep the profits. However, the TV companies have to use a 'question and answer' format; if they simply said "just phone in and we'll select a winner at random" (with no question asked), they'd be committing a criminal offence by promoting an illegal lottery.
You also state that the girl is running 'various events'. Where I live, there are loads of tea dances, discos and other activities arranged in the local village halls and community centres. Some of them are run by, or in aid of, charities but the vast majority are small-scale commercial enterprises run by local people for their own profit. The halls and community centres benefit from the hire fees and the participants benefit by having entertainment provided locally. e.g. a friend of mine, who's in her mid-70s, supplements her pension by running tea dances at several locations. It's known as 'entrepreneurial spirit' and both my friend the young lady you refer to should be commended for their efforts.
Chris