There appears to be such a thing as a free lunch for deployed troops and their families.

Now it’s a matter of feeding them, so to speak.

Some self-professed computer geeks have joined to give deployed troops access to invitations for Google’s free e-mail service, Gmail, which offers an unprecedented one gigabyte of storage that will let them share photographs and videos across the Internet.

Gmail is currently available to the public only through the much-coveted invitations, which let users test it out as Google experiments with the software. Demand for the invitations is so high that they are being auctioned on eBay, and Internet sites have popped up where people barter deeds — mostly good deeds — in exchange for an invitation.

Now, invitations for the free e-mail accounts are available for troops overseas, particularly those serving in combat zones, said Anne Mitchell, president and CEO of the California-based consulting firm Institute for Spam and Internet Public Policy.

To register, troops need to log on to www.Gmail4troops.com and select “request an invite.”