CORRECTED - AmEx testing charge card for those in their 20s

(In paragraph 3 and bullet point, corrects annual fee to $25 from "up to $20"; also corrects benefit packages offered)

* American Express courts $625 bln market

* New card has an annual fee of $25

NEW YORK, Dec 8 (Reuters) - American Express Co (AXP.N), the largest U.S. credit card company for purchases, is testing a charge card for customers in their 20s, courting a $625 billion market with lower fees.

The Zync charge card, which must be paid in full each month, will be officially launched in the first half of 2010, the company said on Tuesday.

The charge card has an annual fee of $25. In contrast, the American Express green charge card -- the company's standard card -- has an annual fee of $95.

American Express is also offering four benefit packages with the new card, targeting eco-friendly customers and those who prefer rewards or discounts on airfares, mobile phones, and restaurants and concerts.

The eco-friendly package has no annual fee, while the others have annual fees of $20. Customers can choose more than one benefit package.

The company said customers in their 20s represent $625 billion in annual buying power.

Last month, American Express announced the acquisition of the low-cost, Internet-based payment platform Revolution Money as a way to offer cheaper options to its clients. (Reporting by Juan Lagorio; editing by John Wallace)