Many workers get excited when their employers kick in a matching contribution to spur them to save in a 401(k).

What few people realize is that Uncle Sam will kick back up to $1,000 to reward low-income taxpayers who save for retirement, too.

The mechanism is the little-known savers credit, which is worth 50 percent of the first $2,000 taxpayers stash in a traditional IRA, Roth IRA or retirement plans at work like a 401(k).

Thanks to inflation adjustments that boosted the income limit for 2007, the credit generally is available to taxpayers who earn up to $26,000 if single, $39,000 if head of household, or $52,000 for couples who file a joint return.

(It’s not available to people who were full-time students more than four months of the year, which crimps recent college graduates who otherwise might snag the credit with a little seed money from Mom and Dad.)

The conundrum is that taxpayers in those income brackets typically struggle to save. But more companies are automatically enrolling workers in 401(k) plans and matching their contributions.

Many of those workers might not realize they’re eligible for the credit – and the Internal Revenue Service isn’t going to alert them, said Kaye Thomas, a tax attorney who founded the Fairmark.com tax Web site.

Joseph L. Salazar, a partner with S&S Tax Service in San Jose, Calif., said he flags returns to remind his staff to probe whether clients might be eligible.

“I’ve never had a client come and say, ‘Oh, by the way, I put money in. Do I qualify for the Savers credit?’ But when it comes up, it’s always a nice surprise.”