Here is what i would do with $4000:
First of all it is very important to watch stocks long term, 10-day, and daily graph and really understand the different sort of breakouts (to the upside) that can occur. A good example is the way Ford has traded over the last 6 months. Notice how it was in a strong long term trend, then started to trade in a tighter and tighter range, around 11 and then broke up and out of that range at the end of February leading to about a 20% move or so.
What I would do if I were you would be to create a simple screen, try the one at Google finance, and screen for stocks with a low price <4, decent volume >100000, and throw in a few other variables like inst. ownership, avg. volume, 52wk price move, etc. and run it at around 9:40-9:50 eastern.
The goal would be to look through the stocks that the screener came up with and look for long term and short term graphs that kind of looked like Fords when it was breaking out.
If you are conseravtive and intelligent and your broker lets you put in orders for 10ths of pennies. You should be able to catch moves of 10-40% every once in awhile while limiting losses. Good Luck.