He was a bum. Bums were "homeless" before the word "homeless" was invented.
He corrected my grammar.
I was so impressed I bought him dinner that day.
Turns out he was a University Professor, down on his luck.
I bring this up, for those who write ad copy.
Proper grammar is nice.
But unless you're butchering the language, you're not really writing copy.
Keep in mine, it's not the WORDS you use, but THE RESPONSE you get.
Yes, AT is a preposition and should not come at the end of a sentence.
But when you're trying to tell a story, and SELL your product or service, the OFFER must shine, not your grammar.