The market for more affordable smartphones is heating up.

Consumers who haven t yet purchased a smartphone tend to be scared off by the price of the phone or carriers requirement for a pricey data plan, says Michael Morgan, a mobile device industry analyst for ABI Research. To push consumers over those hurdles, cellphone manufacturers have cut prices on existing handsets and introduced new lines of inexpensive, feature-rich models and in the process boosted sales 25% during the fourth quarter of 2009.

Carriers are providing another push by adding data plans for quick-messaging devices, also known as QMDs, says Delly Tamer, the chief executive of LetsTalk.com, a site that sells wireless services and handsets. (Like smartphones, QMDs have a keyboard, but they lack a web browser.) For an extra $10 to $20 per month, consumers are looking to phones that offer more features for that price, he says.

At the International CTIA Wireless convention, currently going on in Las Vegas, manufacturers and carriers are expected to announce faster networks and new features to further enhance the smartphone experience. For newbies, here are four affordable models:

1) Palm Pixi/Pixi Plus

(Pixi: $50 on Sprint. Pixi Plus: $50 on AT&T; $80 on Verizon. All prices are after rebates, with a two-year contract.)

Palm (PALM) slim Pixi hasn t been a major seller -- it isn t advanced enough to appeal to most experienced smartphone users, Morgan says. The Pixi is targeted at pulling in someone who had a feature phone and wants to take the step into the smartphone space, he says. It comes with a touchscreen, web browsing and email capabilities and an app catalog that includes Facebook, YouTube and Twitter.

Before you buy, consider that Palm s poor sales in recent quarters have led many analysts to label it a company at risk for failure, says Morgan. If the company goes under or is sold, that could affect the future availability of operating system updates and apps. Palm did not respond to a request for comment.

($99 for an 8GB 3G handset on AT&T, with a two-year contract)

"The iPhone has really done a lot to bring smartphones to a larger audience, says Kent German, a senior editor covering cellphones for review site CNET. Apple (AAPL) iconic handset is east to use and offers a wealth of apps that let users tailor the phone to their needs -- whether they want to find romance or transfer cash. All that data use, however, has put a strain on AT&T s network, leading some users to complain of dropped calls and other service problems.

3) Motorola Devour

($100 on Verizon, with a two-year contract)

The Motorola Devour is a bit like the poor man s Droid ($200 on Verizon with a two-year contract). The full-size slider keyboard may appeal to messaging addicts, while the MotoBlur feature will stream together all your posts, tweets and messages from various social networking sites. But you can t update the Android operating system until MotoBlur updates, leaving users forever lagging behind those on other Android handsets But you can t update the Android operating system until MotoBlur updates, which leaves users lagging behind those on other Android handsets. If you d rather forgo consolidated networking for a fast processor and up-to-date OS, Best Buy currently has the Droid for $100 with a two-year contract.

4) Nexus One

($179 on T-Mobile, with a two-year contract)

Consumers looking for an iPhone-like experience without AT&T might want to consider Google s Nexus One, German says. The Nexus One has a touchscreen and interface on the Android operating system. It's also pricey, but Android is adding new features and updates that will add value to the handset, Tamer says. For example, now they have an update that allows you to dictate emails, he says.