To get a general idea of what to expect, a project such as a full suit of armor could cost anywhere from $200-$600; and a sword could cost $100-$200 just in materials. Most of your time will be spent in the sanding stage if you want to have a nice looking prop; as the fiberglass and sculpting stages are rather quick if done right. The overall time for a suit of armor could run about 200-600 hours depending on skill, size, tools, and desired results. A sword could likewise run from 50-100 hours depending again on the desired results.
Most materials can be picked up at Home Depot, Lowes, or Marine stores
Polyester Fiberglass Resin (gallon): $30
Types of resin
There are two main types of fiberglass resin: Polyester and Epoxy. Polyester, commonly found in hardware stores may cost less and dry in about 15-30 minutes, but destroys foam. Epoxy resin, commonly found in marine stores cost three time as much and dries in about 12 hrs, but doesn’t melt foam.