Restitution of up to $22,000 will be made to Marylanders who were offered a "free" Florida vacation and then charged a $46.50 "service fee" for a certificate for the trip, according to a settlement agreement between a Tennessee firm and the Maryland Attorney General.

The restitution for individual consumers will cover the $46.50 certificate, as well as postage and telephone expenses connected with the vacation offer extended by National Travel, based in Sparta, Tenn., and Lehigh Corp. of Fort Myers, Fla.

In signing the settlement agreement, National Travel agreed to pay the restitution but denied any wrongdoing. Lehigh isn't required to pay any part of the settlement but agreed to all other portions of the consent order.

Consumers filing claims for restitution must submit proof of payments for the service fee, postage and telephone cost to the Attorney General's Consumer Protection Division, 7 North Calvert St., Baltimore, Md., 21202. The deadline for filing the claims is June 30.

The consumer division filed a suit in March 1980 against National Travel and Lehigh, charging they had violated the state's consumer protection laws by mailing an undetermined number of advertisements to Marylanders. The ads offered a "free" five-day trip to Florida for which the consumer had to pay a service fee, travel and meal costs.

The suit said consumers were invited to attend a land sales promotion as part of the trip.