Hello, the best way to find out the limits is to download&install the Demo version and try yourself :-)
IIRC, the limit is 100 elements for 2-D models and 300 elements for 3-D models. The finite elements modelling reinforcement bars do count, too.

GiD is a general FEM pre- and postprocessor. You can register for a free, 30-day full license, i.e., try the unlimited version for 30 days. After the trial period expires (and also before you register), there are also some limits on the number of elements, nodes (I think 1000), and also on the number of geometry entities (volumes, surfaces, lines). You can find the exact limits in the GiD documentation (they change version to version a bit).