there's been good stuff said here but if you're on a budget, well some of that shit is PRICEY. the meters for instance are gonna run you over $100.00 and that only if your lucky or cheap.
the reason you use MH for vegging and HPS for flowering is the different spectrums of light and you CAN get decent results with CFL's, not as good but still good, and lots cheaper.
anyway, you're not ready yet, you need to read some more about light and nute's and air and ...........