We do a LOT of credit card business. Over 90 percent of our payments come by way of charge or debit card. Since we can NOT afford to be unable to accept credit cards, like Monty, we have both GoPayment and Square. Both of these services are free and require no sign up or monthly fees or maintenance fees.
We have ATT cellphone service. Additionally we have a Verizon mobile hot spot. We did this because in some places one carrier's cell service was not good enough, but the other service would work. Again, like Monty, whenever possible (today, almost everywhere) we have found that using wifi eliminates the cellphone issues.
Today, we have a Verifone Vx 670 wireless credit card terminal, a Square Reader, a GoPayment reader, AND a Paypal reader. We simply can't afford NOT to be able to accept cards anymore than we can afford declined cards.
We do a LOT of shows, as pen sales is my primary occupation. We do enough volume that being able to accept debit cards at the discounted debit card rate justifies having the Verifone terminal. IF we were part timers, we would still have both GoPayment AND Square, simply because there is no additional charges to have both and in some places, one reader will work while the other will not.