Dont listen to them, dude. You're shipping is reasonable. I dont think they are taking into consideration the cost of shipping supplies. I personally suggest shipping First Class only (Its faster then Media Mail plus you can put insurance and/or tracking on it as needed.) Stay honest and cool. I'll be watching this one.
create a paypal account is easy otherwise I can take cash but is more recomended paypal so in the future somebody fails to you you can claim your money back