"I say this because $15 is not really a bankroll, if that is all you can afford to put in you should for sure do something else with it."
I disagree with that. Big time. Vehemently, even.
$15 is a roll. What else should the guy do with it? He's found an unneeded $15, turned it into $42, and is trying to move up while minimizing ruin. You're telling him to move up ("just don't go crazy") while telling him he's got no roll. C'mon, man. That ain't help.
$15 is a beautiful start. $42 is frickin' 200%, if y'all allow some bad-at-math rounding.
I say all that, to say, yo Blue: keep winning, don't over extend, and don't let anyone knock micros. You gotta start somewhere, and that start probably ought not include the rent.