How do you determine the actual cost of shipping a packaging weighing less than one pound from china to Florida the shipping company is EMS The seller is chargin me 31 dollars and it seems too hi?

How do you determine the actual cost of shipping a packaging weighing less than one pound from china to Florida the shipping company is EMS The seller is chargin me 31 dollars and it seems too hi?
Yeah EMS is very slow and way to expensive one time i ordered two packages from a site in china called dealextreme one with EMS and just a normal free shipping package the free shipping one got to my house 5 days ahead of my ems i was so pissed. Point blank just go with the free shipping unless they offer UPS, DHL, or fed ex ohh and i live in Panama city beach , Florida so i understand it takes a long time to get from china to FL