The service is an extension of the microblogging firm's deal with American Express, which previously enabled account holders to take advantage of discounts by tweeting about special offers.
"Amex Sync" integration allows users to link their Amex card with their Twitter profile and carry out transactions on a mobile phone or computer.
"We're convinced that commerce is going to be one of the areas [in which] advertisers are going to start using our platform," Twitter vice president Joel Lunenfeld told The Wall Street Journal.
The pay-by-tweet service is being launched with offers on three electronics items - Amazon's Kindle Fire HD, an Xbox console bundle and a Sony camera - as well as with discounted Amex gift cards.
Neither Twitter nor American Express divulged the financial terms of the agreement.