There is a small, but growing, number of retailers that have decided to apply this worldwide. Perhaps GOG is the most noteworthy. Look at anything that’s discounted there and you’ll see their “usual” price, as well as the lowest price they sold it for in the last 30 days before the current discount started. It’s a good rule, makes me more inclined to feel I’m actually getting a good deal, wish more places would do it
You absolutely should not feel bad about doing this. Ever.
If anything, you should talk about it and share your experience, because your experience could help some of those who work manual intensive jobs and are still struggling to get raises of their own.
Remember: If the company isn’t able to fairly compensate its workers, it doesn’t get to have workers. That’s how supply and demand works.