Actually most cash registers start at between $100-$200, and don't do credit card processing, much less SMS receipts, Google-analytics style sales data tracking

Actually most cash registers start at between $100-$200, and don't do credit card processing, much less SMS receipts, Google-analytics style sales data tracking, etc etc etc... The value of Square + iPad beats the pants off what sort of cash register you can buy for $500. Not to mention that when the day is over, you have an iPad.