Starting Jan 26, 2014, new USPS prices for domestic packages (which is anything more than ¼ inch thick).
“Online” is the price if you print the postage at home
“Stamps” is if you go to the post office or otherwise place actual stamps on the package
International rates aren’t changing; just the highlighted domestic postage rates.
For instructions on changing or updating your shipping prices on Etsy and eBay, check out my blog post from this time last year (the previous postage rate increase).
I have been unable to confirm the new price (if there is one) for Priority Small Box Flat Rate when purchasing from a physical post office rather than online.