Retail Prices in the US are almost always before taxes. Most states have a base sales tax (between 4%-8%). Then some states allow for individual counties and cities to add more sales tax on top of that. I'm originally from an area near Seattle, Washington, and the state has a minimum sales tax of 7.5%, and my county added a total of .8% (.6% for a free transit system, and .2% for the Hospital). However, in Seattle, they have added 1.6% (or more by now), some of it is to pay for transit services, stadiums, and roads. Some states, like Washington, allow for special taxes to be leveraged on certain products or services. Washington allows for extra sales taxes on rental cars or hotel rooms.
At least it is not Canada, where there is a 5% National Sales Tax (GST), then there can be provincial, county, and city sales taxes (each compounding on the other).
TEG