Are you sure you got a look at the actual timing belt or just one of the accessory belts. The timing belt is about 1 inch wide and has teeth in it running perpendicular(I guess the accessory belt does too but it is about 1 inch wide and has teeth running parellel). Not visible without removing a lot of covers I think. It doesnt run over the a/c, alt, waterpump pulleys.
Usually the timing belt should be changed as a matter of maintenance at about 60,000 miles appx.
It sounds like it could be plausible and that would be the cost for the repair.
A half-a**** backyard mech should be able to tell you if its the timing belt....if yo know one.
How many miles on it?