Story happened to a relative of mine, many years ago.
My relative once learned that there was a yungerman who wished to join a certain kollel, however the budget was maxed out and they were going to turn him away. My relative did not want them to turn away someone wanting to learn, so he pledged to cover the entire kollel check for him – $500 monthly.
When he came into the office the next workday, he had a message on his answering machine. It was a superintendent of a building he owned, letting him know that a certain longtime tenant had vacated their apartment, and another tenant had been found. The original tenant, however, had been eligible for rent control regulations, and had been paying far below the market value. The new tenant paid the going rate – exactly $500 more per month than the previous tenant did!