Build an SQL Query to help with billing

We maintain approximately 100 databases in SQL 2008. We need to bill each month based on the number of records added to each database. We have been doing this manually up until now. I would like to write a SQL script that will allow my (inexperienced) user to 1) Create a table in the Billing database named by the MonthYear. 2) Set a biggining/ending date range for us to bill. 3) Run a series of SQL scripts that will populate this single table with all of the information we need for billing. Part of the issue is that we can only bill for a database when the month is complete. We may bill for database 1 on Oct 5th because it will be complete through September data. Another database may not bill until Oct 15th because we would not have completed September until then. I have the beginnings of a script attached. It's getting a little too complicated for me with all of the @variables involved. Hopefully it shows you the direction I'm headed. My specific question begins on row 78. I understand that a utility of some sort would be better, however, SQL is the only scripting language I understand. I will need to be able to make changes down the road as we modify our process, add/remove county databases etc. This has to be accomplished in SQL Server query.