We CANNOT recommend the commercially available scripts from Primenet. They are sloppy, user-unfriendly, and aesthetically lacking - not to mention they charged my client big $$. It's hard to understand why iBill recommends them.
I would say not to spend any money on acquiring iBill scripting. Most of it can be built or found open source. iBill will send you info on how to work with their processes - without cost.