I didn't see any post about this on EGL, but I thought it'd be useful to everyone who's planning to sell/buy from the US. There was a price increase and weight change in postage and parcels for USPS effective on Jan 29th, 2013. You can see the details here:
http://support.pb.com/library/PBKB/files/Support%20Center/pitney-bowes-quick-guide-to-usps-prices-2013.pdf and
http://www.pb.com/docs/US/pdf/Microsite/Postal-Information/Postal-Chart-FINAL-2013.pdf .
The change of price to international shipping is especially significant.
[edit] Beginning the week of August 5, 2013, the U.S. Postal Service will stop delivering mail on Saturdays, but will continue to deliver packages six days a week. Saturday mail delivery to P.O. boxes will also continue.