If you want good quality, go
Jayrob kit,
http://laserpointerforums.com/f39/fs-diy-green-kit-host-heatsink-easy-assembly-22520.html
O-like.com Module
90~100mW Green laser module£>5¡«500mW green laser module£>Laser&lighting products£>www.0-like.com
You can get 50mw, 100mw, 150mw