I really don't know. I usually go to the post office in the morning and ship and let the winner know how much it was when I get home. If I had to make a high end guess, I would suppose $5. Purely a guess.
The reason for my guess is the size and weight. It is approximately 12in long by 8in high and 5in across. Feel free to bid anyway. I can't make it free but I will work with people. Nice people. Lol.