Walmart is hoping for a greater presence in your living room with a more affordable Chromecast competitor called the Vudu Spark. Unlike Google's streaming stick, however, the Vudu Spark will only play content from Walmart's own movie rental service.

Already on sale at Walmart stores across the U.S. and via, the Vudu Spark is priced at just $24.95. To attract new customers, Walmart is running a promotion that effectively makes the Vudu Spark itself free; it'll give you $25 in movie credits over a five-month period.

Just like the Chromecast, Roku's Streaming Stick, and Amazon's Fire TV Stick, the Vudu Spark is a little dongle that plugs into an HDMI port on the back of your TV. It has a dedicated remote and is powered via USB, and it supports 1080p video with 7.1 surround sound.

It sounds like a great deal at $24.95, but the Vudu Spark is nowhere near as functional as the competitors mentioned above. There is no Netflix, no YouTube, no HBO Go, and no Hulu Plus. In fact, there is only one service — and that's Walmart's own Vudu.

"Vudu's app launches automatically as soon as the device successfully connects to a Wifi network," GigaOM reports, "and there is no mention of any way to load any additional apps."

It doesn't seem like there will be a big market for Vudu initially; I can't imagine anyone would buy this over a Chromecast or one of the other do-it-all streaming sticks. But I could see Vudu customers combining one with an existing device to access Vudu content.