Rainy Monday Morning Riddle

It’s Monday and I am finding an excuse to write something. I heard this riddle while listening to Car Talk on NPR. Here is the riddle and it’s up to you, my four readers to solve it….. and you must show your work. Now, if you listen to Car Talk and already know the answer keep your trap shut and let the others have a chance. I’ll be moderating comments here at the blog and will only publish them after enough time has passed to give you a chance to answer. Here we go.

Recently I had a hankering to read Edward Gibbons' three-volume set, The Decline and Fall of the Roman Empire, no small undertaking considering since there are exactly 2,500 pages of text and illustrations in each volume.

Sadly, as I reached for them on the shelf I could see that mold had damaged every page and cover from the front of volume 1, though that cover was undamaged, to the back cover of volume 3, though it, too, was undamaged."

I called the local book repairer and he said that it would cost a penny a page and fifty cents a cover to repair. He says, 'Bring the affected volumes over and come back in a week, I'll be all done.'

So I show up in a week prepared to pay the bill, and it's about half of what I expected it to be. The statement that it was half is a hint. The question is how much was the repair?

 
 
 
UPDATE
Here is the answer.