I learned to play Blackjack long before I started wagering on sports. When I play blackjack, it is for a few hours of entertainment only, so I keep the bets small ($5 -$20) until I'm ahead so my $$ and entertainment last longer.
When I first began wagering on sports, I had this same small-time mentality. I played too many games but with very small wagers on each one ($10-$20). I am still a recreational gambler on sports, not a pro by any means.
Over time I realized that, unlike Blackjack where the player is playing entirely on probability, sports can be handicapped for line value, situtations, match-ups, etc., and that there are strong plays and weak plays that should be bet accordingly. I now play fewer games at $50 - $500 a pop. Small potatoes compared to many in the Rx, but I have increased my wagers with time.