Sales of prepaid smartphones in the US consumer market have risen dramatically, doubling in the last year and "continuing a string of more than 12 quarters of triple-digit sales increases" according to a new report from market analysts NPD. Prepaid phones -- defined as either premium smartphones such as the iPhone bought outright to avoid a contract or low-end smartphones aimed at lower-income consumers -- increased 11 percent in year-over-year in the first quarter of 2013.
