Hydro is a very complicated way to begin growing. THG hit the main point. WHat size growing space do you have. Next you have to actually understand the minimum that one must provide for MJ to grow indoors. As far as light, air, water, food, security. Its like getting an exotic pet.
Are you capable of maintaining a consistent schedule for at least 3 months? Are you financially able to buy everything the plant needs when it needs it?
Have you ever owned an exotic animal?
If you have never grown you really want to read up on everything you can. Im sure you have since your taking an interest this means you have been filing away bits of info you've seen online, but sit down and think it all out.
Come up with a game plan. Hydro is complicated only beacuse you either have to buy a good setup or be good at building one. You have to buy slightly more expensive materials since hydroponic is considered a step above.
Why not just go with soil? Indoors soil means you will have to understand how plants feed through soil and how to give em to em just right. It seems like it would be messier but messing aroun with bins of fertilized water is kinda the like.
Also with hydro you really invest more up front and since it would be your first dro setup failure is highly likely. Then your dissappointment would be even greater so. Further ending in giving up.
With soil you can get your materials at HD or Lows. Get a good organic soil with very little nutes if any at all. A good fast release all purpose organic plant food. You can get HID lighting if you prefer or go with CFL, LED and T5. Learn the benefits and drawbacks of each of the types of lighting listed above and MAKE YOUR OWN DECISION on it. People will fight to the death over their favorite lighting but it ultimately comes down to what you feel is best.
Go ahead and get pots up to 12" they should be sufficient unless your going big. (This is where the question above comes in real handy)
But hey dont let anyone not even me tell you what to do. I have gotten ish for my setup and I just poste about it 24 hours ago. Happy Growing!