The 10th one The 10th oneSolutionThe 10th One Is Free is a M

Solution

The 10th One Is Free is a Metropolitan Diary by Brian Gatens.
It states the following-

Dear Diary:
The 10th coffee is free. Ring me, punch my card. A punch each day, good or bad. After two weeks, a modest reward.

I hold the card to the light and track my progress. One? Why do I bother. Four? I swear I had four yesterday. Eight? I’m sure I will misplace it before Friday.

Nine? Today is the day. I unveil the card from the depths of my wallet. Before I am even able to announce my triumph, the barista is already celebrating. “This one is free!” she exclaims.

Taken aback, I compliment: “Gosh, you count fast.”

“It’s my job,” she says dismissively.

Two weeks of punches and so much life in between. Time to start anew.