It's the market that controls the prices. Many shops won't rise prices because they would lose customers, if many others don't.

But after an agreed price rise, it's a different situation. It takes more time to sell cheaper, because the shops want to pretend that stuff is expensive just a bit longer.

Just have some patience and try to avoid the expensive stuff, as much as you can for some time. The biggest risk for shops is that someone finds alternatives and actually never again buys the previous product. They'll panic and prices will fall drastically.