Zimbabwe and other 'developing' nations facing extreme inflation have tried that. They've reset their currencies dozens of times trying to force things to just stay at a normal value. But the economy isn't just made up numbers (mostly), there's tangible supply and demand driving it.
What happens when you say the price of each item can be no more than __ but the supply/demand is driving inflation? Businesses just close down. Because to not inflate prices and sell for the 'legal' price would be to lose money on each sale. Whole economies just collapse, nobody can buy shit, people starve.
You're probably trolling, but there's your real answer anyway.