I have been playing magic off an on since 1999.  I primarily play Modern and Commander, and thats what most of my wishlist is geared toward.

For trades near or under $15 I will ship in a standard envelope with a toploader for protection.  For trade near or over $20 I'll use a bubble mailer and get delivery confirmation.  If its in between, I'll generally ask you what you prefer (both do stamps, or both do tracking).