Not only doable, it's REALISTIC!!
I trade TF, YM, and NQ. Not automated. Intraday trading only(for indexes), flat at the beginning of the day, flat at the end of the day. I "normally" take 15-20 trades per day combined across all instruments, with no more than 8 contracts on simultaneously across all instruments. I do not trade ES for several reasons, the primary being I do not like the .15 tick differential between the ES and SP. That's just a big arb, and l believe is cause to many of the quirks and problems pointed out by others associated with trading ES.
Just think about today, 5/16/13 ...
TF had a RTH range of 990-881.5, 85 tics. Assuming just a straight line with no counter movement, that's a per contract dollar value of $850
Lowly YM had a RTH range of 15278 - 15192, 86 tics. Assuming just a straight line with no counter movement, thats a per contract dollar value of $430
NQ had a RTH range of 3019-2996.25, 91 tics. Assuming just a straight line with no counter movement, that's a per contract dollar value of $455. Interestingly, today the range in each of these instruments was a straight line high to low in the final hour. LOL The previous 5 hours or so of RTH trading was just bonus!
So do the math for YOU... using YOUR system(s), techniques, and methodologies how many tics (total cumulative in a day) by 1 contract would YOU need to keep for $500 total? Be sure to include commish and fees. How many trades would YOU say YOU would need based on YOUR style? Do you have the discipline and inspiration to do this? Don't forget counter move opportunities too. Or are you swinging for fences?
My 2 biggest words of advise...
1) have many tools in your tool belt and knowledge/ability to trade different instruments. Be prepared to trade minimal ranges and/or know how to trade other instrument(s) where action is suitable to YOUR style.
2) if you have a NEED to pick tops or bottoms, as sooooo many on this board try, you should not be a trader, futures or otherwise. Picking market tops and bottoms are for ego-maniacs and liars. The ONLY tops and bottoms that matter are bikinis. When YOU determine to buy or sell, it has nothing to do with bikinis!
Trade On!