Try a few of the 9 line nickle machines.
Your money may got faster with nickels, but your wins are also larger.
I remember sitting down once at a nickle machine, thinking it was still pennies, put in my $20 and started playing with 2 coins per line.
It was a nickle machine and I got it up to 1500 nickles within a half hour of playing, before I realized it was nickles and not pennies!
Of course I quickly cashed out and got change at the change machine, and then moved on. I think I went to a different nickle machine again, and won a few more extra dollars on that machine too.
Just give the nickle machines a try next time you play the slots, they're not too bad on payouts.