My advice is to read some articles about deckbuilding on the cheap.
Nate Heiss had a really good article for building decks for about 20 to 30 tickets(about 20 to 40 dollars, markets vary) for MTG:Online.
Battle Royale over at
www.starcitygames.com will show you how to build some cheaper decks, too.
If possible try to do things that are cheap for you, like "Ghetto" tournaments(not PC, I know) where somebody has to build a deck with a value under 30 dollars.
www.pojo.com also has some good articles about Peasant Magic, a rareless, 5 uncommon format for people without a big budget. Abe Sargent writes about it occasionally at
www.starcitygames.com That is a favorite website of mine, another good site is
www.magicthegathering.com Jay Moldenhauer-Salazar has some good articles about tweaking preconstructed decks and the Tribal format.
One final thing, maybe reading some of the more referenced articles about Magic would be reccomended, like "Who's the Beatdown?" and "The Danger of Cool Things". Good luck!
Edit:Shoutout to Chris Romero, a budget deck builder. Look him up.