Dan's correct.
I sent off 6 or 7 boxes of cards (full 3200 & 5000 boxes) to friends for thier kids, neighbors or local charities.
The cards were just taking up space so I figured to move them as a good deed to kids who would appreciate them. Sent them all via media mail
figuring they were all printed material. Each one cost maybe $5-8 to ship.
Came in the next day and was told they do not fit in the media-mail classification and now had to pay $15-20 each to ship.
Since I already told the people the cards will ship on my dime, it cost me over $100 for my good deed
Edited for spelling