Re: help!!!!
Cheapest way to go is to build your own and learn from the experience on this site and BE SAFE. If you're 13, you might be mature and able to handle stuff like these, but your friends might not be as mature as you and people can get hurt.
Learn a lot first - it's more fun when you really know what you're doing and why. Best of all, learning is free!
When you really know what you're doing and can figure out most stuff for yourself, you can find places here where you (or your parents, more accurately, since you'll need to order with a CCard) can order the parts you need, and you can probably have a very nice little device for under $75.00, that you built yourself.
Just remember that these ARE powerful "toys" and you can permanently hurt yourself or others if you don't know exactly what you're doing. That said, there's a lot of other people on this website that are your age building projects with lasers that amaze and impress me every day.
As for laws - if you keep the thing in your house all the time, you'll be safer. Even where there aren't specific laws about it, people can get nervous, and if the wrong person gets nervous about something they've seen you with, they can make as much trouble AS IF there was a law, so pretend they're illegal and you'll be safer!
Welcome to the board. There's a lot of info here, and a lot of wisdom in the members, and most are willing to share - but not spoonfeed you. Learn & have fun!
Dave