Target audience and pricing

Since there is also a pop magazine out there with a target audience of young teenage girls, I want to make my magazine available to a wider audience. I don't want to just target adults because I don't think as many adults would buy the magazine compared to teenagers but I would prefer to target an audience of 16 - 21 year olds. This way I would targetting a teen audience without making it too ideal to be a 12 year old girls magazine.
The magazine would have to be fairly cheap as the age bracket that I am targetting does include university students who would probably not be able to afford a £3 magazine every week. The magazine would have to be a weekly magazine as the music industry is always changing and  if it were a monthly magazine, other companies would probably be likely to get the information out to it's audience quicker.
There is also now added competition in gossip magazines (such as Heat) as they are also covering artist interviews and information and giving their own ratings on albums and singles so I need to create something that looks more serious and more like something that people are going to want to get the opinion of. I need to create a magazine that would be credible in the music magazine world.