[the_snooze]

>I'm not from the US, so i'm honestly curious, does sales tax really change that often?

It changes more often than you'd expect, but it's not daily. Perhaps yearly, but certainly across space too. Government in the US is very "layered." Our states are basically autonomous countries free to set their own taxes. Additionally, many states give sales taxation authority to municipal governments. There's little coordination across states or municipalities, so you might pay 7% sales tax on restaurants and 1% for groceries, then drive across the river to a different city/county and pay 6% and 2% respectively. There are also sales tax holidays where the tax is suspended for a given period within a state, but only for certain items.

Basically, it's very complicated due to the lack of coordination between levels of government in the US.