anyone have any idea how this new payment to the cellphone works...i need to find a quick and easy way for domestic customers to pay me while on site so that i dont have to beg for my money...

if i ge tthe electronic service sheet and invoicing done while on site i can ge tthem to pay me at the same time...everyone has new fancy phones i am sure there must be a way...having a credit card machine is expensive and old technology...any ideas?