Chirpify, which was recently selected as one of BTN's top ten technology companies to watch and has a large bank deal on the horizon, has begun a social commerce campaign for a book about the future of money.

Using Chirpify's social commerce and payment platform, David Wolman, the author of "The End of Money," is selling digital copies of his book for four days on Twitter. The sale started Wednesday.

Chirpify, a Portland, Org.-based online commerce startup, helps move money from buyers to sellers over Twitter and Instagram. To authorize a purchase, a Chirpify user crafts a reply message, like "Buy," while he's in his social network. Chirpify integrates with PayPal.

Watch a demo of the service here.

"The End of Money" costs $5.99.

To date, banks have largely stayed away from financial transactions over social media.

Vantage Credit Union, a Missouri based credit union, offers members the ability to do some of their banking via Twitter. The service, called tweetmymoney, has been available since 2009.

Meanwhile, Citi queried consumers through its official Facebook and Twitter channels in July: If you could do your banking on Facebook — would you?