Best way to ship is in a small metal box...like an Altoids box. It protects the matches from getting smushed.

Next safest way is to wrap the matches in foil, but that doesn't protect from smushing. One ebay seller took a small stack of corrugated cardboard pieces (6-7 pieces), cut into rectangles (maybe 3"x3.5"). He cut openings out of 2-3 pieces, just a little larger than the matchbook. He stacked 2 pieces of cardboard, then the 2-3 with the holes...and put the matchbook in the opening, then 2 more pieces of cardboard. Wrapped tape around the whole bundle. When the matchbook arrived, it was snug as a bug in a rug !