Query Returns Every Possible Combination

Hi, i'm hoping someone here might be able to help me. I have come to a bit of a dead end with a database application i am working on.

The database is a delivery newspaper management system for a newsagents. Basically i need it to link customers to the paper they wish to receive, organise them into delivery rounds, and produce a bill for each customer based on the newspaper they get delivered.

The problem I am currently having is when it comes to the billing.
I have:
a table that stores customer details
a table that stores newspaper details (inc. price)
a table that stores the customerID and then the NewspaperID for each day of the week. (since not all customers get a paper everyday of the week)

If a customer gets two papers then two entries are made in the requirements table under there CustomerID)

Now to fetch the price of the newspaper the customer is down to receive each day and then add these all together is where i have been having trouble.

After many different attempts the solution i am currently using is this. I have a query for each day of the week. Each query take the customerID from the requirements table, then the newspaper price from the table storing newspaper details.
The problem here is that the query returns the CustomerID next to every newspaper in the database. I found the solution was this. I added the newspaperId from the newspaper details table and in the criteria stated "[tableRequirements].[NewspaperID]" And this worked perfectly.
Untill i added a customer who gets two papers. As far as i can tell the query is returning all the possible combinations of which newspaper the customer should get.

Any help with this would be greatly appreciated - thanks in advance.