MarketPress Calculate Sales Tax

Correct me if I’m wrong – I hope that I am, or that there is a buddy plugin to use – but if I’m using Marketpress there is no way to calculate sales tax per state or only charge a set/flat rate of sales tax if the purchaser is from a certain state – otherwise not charge a sales tax. Is there any flexibility in sales tax or a way around sales tax issues? My client is going to have an online store and sell to all 50 states…
Thanks!
Kate