trading concepts and learning
if you would like a broad overview of how to approach learning trading and some ideas to get started, you may want to check out :
http://gleanusers.vanillaforums.com/discussion/164/gleaning-for-groceries-trading-in-everyday-life
also if you are serious about...
the most affordable platforms are open source if you are wanting to experiment and already have a broker. activequant is a java project, tradelink is my c# open source project. tradelink - Google Code
You can backtest automated strategies, develop discretionary ones, record and playback...
If you're proficient in java, you could do it in a few days easily. The IB api is pretty straightforward and there's java interfaces available.
As a side note, I have clients who do this already with TradeStation and 3rd party brokers (including IB). You wouldn't need to write any new code...