How does all you can eat affect consumption?

There’s probably a study out there that’d answer this for me, but I’ll ask anyway. Let’s say every month I buy a $89 unlimited subway pass and ride the subway 89 times. My effective cost for a subway trip is $1. If I had the option to buy a $1 ticket, how much would I spend a month? I’d probably spend less by making active choices to avoid the subway. Not sure whether the true value (less mobile on subway = less happy) would be worth it, though.