Rat rods are somewhat of an anti-traditional version of the so-called hot rods of the 40's, 50's, and 60's. Rat rod purists believe a true rat rod should be built not as a show car, but as a daily driver with emphasis on function instead of show quality. This doesn't mean that all rat rods are unpainted bare bones cars without any fenders or flashy paint jobs.
Many rat rods are built on a relatively small budget. Small block Ford and Chevrolet engines are plentiful and won't cost a small fortune to bring back to running condition.
The body of your rat rod is probably the most important decision you'll make. If you have your heart set on a rat rod built from a 1930's coupe, you will need a much larger budget and probably a lot of patience. It will be extremely time consuming and expensive to find models from this era. Even 1940's coupes are difficult to find in this day and age. There's a much broader selection and availability of other cars and trucks that will make a great rat rod project. Old Ford, Chevrolet, Dodge, and International pickups will all make outstanding rat rods.