Evaluating easiness, performance for django/RDF, etc

Greetings,

I need to quickly evaluate easiness of building and running an application with semantic vs semi-semantic vs relational DB management tools.

How long would it take - for a django/python, Java, C or Lisp professional - to create a very simple API - just a twitter-like or google-like box for entry of words with prompts from my DB, to be placed in a separate table that could be queried as a part of the database?

How much would it cost?

Any advice would be greatly appreciated.

Thanks, Irene