With textPlus, talk is more than cheap. It is free.

This company, which brings free texting and free calls to the masses, announced an $18 million round of funding today. The app brings free mobile communication to anyone with a connected device using the signal from 3G/4G/Wifi networks. It can bestow phone capabilities on iPods and tablets, as well as Android devices, Windows Phone 7, and Nokia products.

For those that already have a phone, textPlus can be used to talk or text for free, app-to-app. This is useful for staying in touch with friends living abroad, as international phone charges can be expensive. The company’s most well-known product provides group text messaging for people across multiple devices, without using SMS protocol. It also offers social features and photo sharing.

The app is sponsor-supported, which is what keeps it free. It serves 110 million people worldwide through the open network, and the recent boost will be used to enter new markets. Raine Group was the primary investor in this round, which marks textPlus’ fourth round of funding.

Kleiner Perkins Caufield & Byers, Matrix Partners, and GRP were former investors in textPlus, and the company has raised a total of $46 .3 million.

The parent company was founded in 2007 as Gogii. It has since rebranded to textPlus, to match its flagship product. The team is headquartered with Marina del Rey, California.