Beginner needing a bit of guidance.

I have built my bubbleponics system and now I need grow medium, ph meter, ppm meter (proper name?), and light setup.

I plan to use red lava rocks for my grow medium as their is nowhere local to get hydroton locally. I will wash it and what not before using it, but is there anything really wrong about using it? I've read good and neutral things through research...

I don't know if I need a special ph meter or not, but the truncheon that people love is FAR out of my price range. I'm thinking like 10-20 bucks if possible.

Are the ppm meters known as EC meters? I am starting out by growing tomatoes, do I need one for this? Is there a cheaper option for these?

LIGHTS! Ahhh! haha. I know HPS is preffered for veg but is there a cheaper alternative to use? I am growing 3 plants in an 18 gallon rubbermaid tub. It's roughly 2' x 1.5'. Can I use a collection of MH lights or similar? I have a timer I can set them on. I don't want to "skimp" on them but I don't know that 350 dollars out the gate on lighting is what I need to do. After a few grows I will be willing to put that money into my setup.

Lava rocks break down rather quickly. You'll find yourself with lots of red sand in your reservoir. They'll work, but hydroton is better.

You can get a EC/PPM meter for around $30. I got the one from HM, and it seems to work fine. Don't forget to get calibration solution. http://www.greners.com/nutrients-additives/testers-ph-ppm/tds-ppm-ec-meters/tds-3-handheld-tds-meter.html

The best option for pH in your price range is the drops. http://www.greners.com/nutrients-additives/ph-control/ph-test-indicator.html

Also, check for a home brewing store in your area. Many of these places also sell hydro supplies. Sometimes places advertise that they have brewing stuff more than hydro stuff.

Funny enough, the state im in it is illegal to brew. One of my other hobbies...