What material is available that is much like children's playdough that
I can use for casting or pouring wax in to create a form of a small
object(2-6 sq inches. I would like to be able to reuse the material
time and time again. I would like the material to show more definition
as well.

There are a huge variety of products. You need to clarify a little
more regarding reuse. Do you mean reuse the mould time and time again
or do you mean reshape and reuse.
Some of the cheapest moulding materials are;
1.Plaster of paris. Available at most chemists. This obviously sets
hard and you can reuse the mould many times.
2. Any modelling clay will also do the job and can be reshaped.
3. High definition work needs a room temperature cured (RTV) silicone
moulding compound. These normally comes as thick liquids.You pour them
over your original and they set into a highly flexible mould that can
be reused again. They give the best definition but are the most
expensive products.