Ok, average U.S shipping cost then?
These are the most common prices and shipping times in my experience for a single figure. Note that some are too large or heavy for SAL
SAL Unregistered: 500 yen - 2-5 weeks no tracking
SAL Registered: 1000 yen - 2-5 weeks with tracking
Airmail: 1500 yen - 5-10 days with tracking
EMS: 2000 yen - 3-5 days with tracking.
Adding a 2nd figure in my experience generally increases any given price by 50%, but has a decent chance of pushing you out of SAL availability. There's something available for larger/heavier packages, called SAL Parcel, but it's never worth it bc it usually only costs 400 yen less than EMS for the package.