ArcWeb Services can be evaluated for free.
If you want to learn about GIS you can access to free training from ESRI and also evaluated for free and learn about geocoding and advance GIS:
http://www.esri.com/software/arcwebservices/index.html
After you create an account you'll be able to start using it. ArcWeb Services comes with all the data you need from demographics to graphics as well you can add data.
ArcWeb Service can also be use by HTTP requests only.
Cheers
Al