I know that this doesn't affect an average PBS swap, but I thought some of you might sell on Ebay or other sites.

Rates go up 1/27.

Here's the link on the Forever Flat Rate Boxes.

https://www.usps.com/ship/prepaid-forever-priority-mail.htm

If whatever you're shipping fits in a Regional Rate A box, that is always cheaper than a Medium Flat Rate. I think the post office does pretty well on the flat rates, when a lot of times with lighter shipments it would be cheaper to ship non-flat rate.

True, Flat Rate is reasonably priced and easy so I tend to ship that way.  But occassionally I realize the package is very light and probably could have traveled cheaper (and just as fast) via a different rate.  Sometimes the 'easy' part is worth a bit more shipping cost...but I really should check out some of those other options!  Not sure about the Regional Rate catagory, most of what I ship Flat Rate is to the other coast or APO...but I'm going to check it out!

Regional Rate A maxes out at $9.62, it is the same as the PM 2lb rate, always cheaper than MFRB. Regional B is the same as PM 4lb rate and is always cheaper than LFRB. Regional C boxes are HUGE and cost a fortune unless it is someone nearby.