First decide what your prime objective is with this thread. If you want kids to benefit from this set of books, then donate it as is where is. No need to set a high price for that and definitely no need to bring up Allah into these petty matters. Give it for cheap to someone who cannot afford it but is willing to bring up their children educated. If you want to do business, then that's another thing. But DON'T mix these 2 things up. You can either do business or show concern towards kids. Pick one!
It's not a used car or collateral which will fetch even half it's price. It's a set of old books. It's like the time you quoted me X amount for a set of earphones and told me I could get it for X+more cash just because they are unavailable in the market. My friend, I later found out they were much cheaper than that.