Filled with holiday merriment, T-Mobile has decided to pass their own excitement on to their customers by putting together a bunch of cheap Android phones and affordable data plans to go with them. Four smartphones, each under $100, and two new data plans set for the average family (if they’re heavy data using families, that is.) For between $10 and $30 extra a month, customers can get 200MB of web traffic or unlimited data.

“We’re heading into this holiday season with our strongest and most affordable lineup ever of Android-powered smartphones,” said Cole Brodman, chief marketing officer, T-Mobile USA.  “Combine that with low-cost data service plans and even easier ways to give T-Mobile products as gifts, and we believe families will make the move to smartphones—enriching how they communicate in the new year.”

Looking at the lineup, it appears a pretty sleek offering. T-Mobile Comet appears as a cheap “My First Smartphone” offering, also running at $200 for people who don’t currently have plans with T-Mobile. Next on offer is the LG Optimus T, which brings voice-activated dialing and command sets to the fray. And the tiny, slim-profile Motorola DEFY—scratch- and water-resistant as well as dust-proof, for those people who need to take their phones into the jungle, desert, or deep sea. Finally there’s the Motorola CHARM with MOTOBLUR sporting a heavy messaging interface with a QUERTY keyboard.

Combined with the new data plans, these should prove pretty enticing to users who haven’t yet made the jump from standard phones to smartphones.

For those so inclined, T-Mobile has a press release outlining these new offerings. Showing how Android phones are doing a very good job of producing a strong handset market, crossing manufactures and giving carriers a lot of leverage to customize plans and phones to their customer base.