Don’t be surprised if custom mobile greeting cards start becoming available through ProFlowers, Red Envelope or Provide Commerce, which owns those flower and gift brands, has purchased mobile app maker Sincerely.

Cofounder and CEO Matt Brezina told The Wall Street Journal that the deal, for an undisclosed cash amount, made money for the founders, the 14 full-time employees, and the VC backers. Sincerely had raised $5.5 million in outside investment and reported 3.5 million registered users, 6.5 million app downloads, and shipments to more than 1 percent of American households.

Sincerely’s mobile and Web apps appear to mesh well with Provide’s offerings. The apps include Sesame, which lets you send physical, themed “beautifully designed gifts,” such as an Ultimate Unwind gift set for having a “relaxing spa day at home.”

Other apps include Postagram, Ink Cards, and PopBooth. Postagram uses photos from your phone or computer to create real postcards that do not need stamps, Ink Cards similarly generates personalized greetings on physical cards, and PopBooth allows you to send photostrip cards from your mobile device.

Brezina said that he decided to sell because of Provide’s infrastructure and customers. Another, more personal reason: he “recruited people who dropped out of college,” and their willingness to leave school to join his startup kept him up at night. Now, he says, they can point to this buyout as a “win.”

Sincerely is expected to increase its mobile commerce app output for Provide, since the company’s brands do not currently have any. Sincerely’s employees will join Provide, although the Sincerely brand will remain. Provide, whose other brands include Shari’s Berries, Cherry Moon Farms, and Personal Creations, is owned by Liberty Interactive, which also owns all or part of QVC, Trip Advisor, and the Home Shopping Network.