OK, the guy's smart enough to hang out with hot engineer chicks, but...
... if he's willing to paw through a pile of change every day, would he be willing to devote the extra-strenuous post-workout effort to carrying home those three empty water bottles? He could refill them and take them back the next morning. It's not the money, it's the expended time & effort.
Plastic bicycle bottles might do the trick too. 49 cents at Goodwill.
Remember in the ancient days of watching a baseball game in the stadium, the roving food & beverage guys would carry small mechanical change holders on their belts? They'd push down on its levers to deliver a quarter or a dime or a nickel, one coin per push. Maybe you could find something like that to hold your small volume of change for quick dispensing.
I keep our change in a small custard dish. Every Friday when we buy our Costco pizza I pay with as much of the change as I can.
Yes, he was crazy [-]smart[/-] enough to get connected with a woman who analyzes everything. In fact, one of the topics during our first meet (4 hours of talking in a downpour at a clambake) was wave mechanics and fetch on Lake Ontario, described in detail 
