Not nearly enough information for an opinion. Edition, date and condition would be the minimum, and using a book site like abe would be your best first resource. Bear in mind that book selling sites only have prices people want, not the prices things actually sell for, which is often much less.
Go to A Libris or Abebooks and put in your information. You will find prices ranging from $1 to $1000 for some books. As AF said, it depends on condition, rarity, etc. and you won't often get the high price you think you want.
The upper limit is 1MB. But somehow the pictures on the original post are now visible. They appear to be mid 20th C or slightly earlier editions, and I'd not expect them to have any more value than reading copies. The Decameron is a good read, I think it was an edition from a similar period that I first read. I am not familiar with the other books, not having read them.
