Well, think that one through: if your advertisement says "Text 12345 to 45678 to donate $10 to the Red Cross", and you do so, and then your itemized cellphone bill says "Red Cross: $20", what is your reaction likely to be?<p>Merchants foot the bill for transaction costs to encourage transaction volume.  It is the same reason I quote my prices as $29.95 not "$29.95 plus whatever your credit card costs me to process."