Quote from JangoFolly:
You can open a forex mini account with less than $2,000, but that doesn't really help you with trading e-minis. If you don't have any experience trading intraday in high-volatility markets, I would respectfully suggest that you do some paper trading and get a feel for the markets until you save some more money.
With $2,000 you're going to be uncomfortably close to the intraday initial margin on a single contract, and you won't be able to swing the overnight maintenance margin. There are some firms that offer $500 intraday margin on the e-minis, but they're really not doing you a favor if you're inexperienced. The four major e-minis each have a different intraday personality, and you will definitely lose some money figuring out which one is better suited to your trading.
IB is a great brokerage, and they don't kill you with software fees, etc. IB data with QuoteTracker is a great low-cost combo for starting out. Also, IQFeed has a reduced rate for QuoteTracker customers.
Good luck.
Afterthought: The margins on treasury futures and grains are much lower than for equity index futures; however, you can get your ass handed to you just as quickly in those markets.