What is the best way to combine shipping like this...

Bascially I am going to be selling primarily two different products: scrapbook pages and albums. I sell them on ebay now, and since the individual pages are so light, I send them Priority Mail and just charge $5.00 for one, and 50 cents more for each page. I may even make thea free. The albums usually weigh about 5 or 6 pounds so I do calculated shipping on those and let them choose if they want Parcel or Priority. If someone buys an album and a page, they just pay the shipping costs for the pages. What would be the best way to set this up on here to give different shipping discounts to different products?