Well,

I too would agree with Keeko about your frist grow being with some free seeds out of a some weed that you or a friend has bought. Your first grow is a learning experince that you can expect to make a mistake or two.
Once you know the game then you can drop some cash for really good genetics. Where to buy well there are over twenty or thirty companies selling seeds over the internet for you to choose. How much should you spend? That is a very hard question to answer since there are hundreds of different types of seeds on the market each priced differently. You will have to do a little reseach on own to make a choice.

Loco