I was just watching this video. At the end, they are promoting a t-shirt and say:
"The offer is valid through July 28th"
Now, I've heard this said before but never really given it much thought. It's not really used in the UK, we'd just say:
The offer is valid until...
The offer is valid up to, and including,...
The offer is valid [date 1] through to [date 2].
There is a similar question here: Through (inclusive/exclusive)
Is is grammatically correct or just an AmE colloquialism?