Will it matter to brands if the consumers they try to reach through advertising turn to prepaid smartphones? In the first quarter (Q1) of 2013, year-over-year total smartphone sales rose 42%, attributing 36% of the unit volume increase to prepaid smartphone sales, according to The NPD Group. The numbers released Wednesday point to year-over-year prepaid smartphone unit sales gains, accounting for 32% of total smartphone unit sales. Some of the plans are offered by smaller companies, such as Republic Wireless.