Mobile shopping options and free shipping offers made buying goods online too convenient to pass up last year.

Consumers put their digital wallets to work to the tune of $161.5 billion for all of 2011, and $49.7 billion in the last three months alone.

Altogether, e-commerce spending in 2011 was up 13 percent from 2010, with online shopping surging 14 percent year-over-year in the fourth quarter, according to market research firm comScore.

“The fourth quarter of 2011 capped off what was yet another strong year for online retail, one in which every quarter achieved double-digit increases versus the prior year,” comScore chairman Gian Fulgoni said. “Price and convenience continue to be the critical value drivers for e-commerce, and unless those conditions change we can expect to see more channel-shifting to online in 2012 and perhaps even an acceleration in the current growth trend.”

Fourth quarter growth was fueled by 10 different $1 billion-plus online spending days, including Cyber Monday which lived up to its name and accounted for $1.251 billion in e-commerce spending, comScore said. The company partially attributed growth to consumers’ growing predilection for shopping via tablet or smartphone, a clear trend for 2011 and beyond.

Consumers also chose not to pass up free shipping offers, as the percentage of e-commerce transactions that included free shipping rose to 52 percent for the year, an all-time high. The “Digital Content & Subscriptions” product category grew by more than 18 percent year-over-year and was one of the top performing categories for the year. Amazon and Apple likely contributed significantly to the trend, as the two companies have sold boatloads of devices for consuming digital media.

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