If something is saleable, it means that people will want to buy it.
Saleable things are usually good and useful. People like to have them.
Examples:
The toy is saleable because it is fun to play with.
The book is saleable because many people want to read it.
The saleable fruit is always sold out quickly at the market.
The saleable car is the one with the most colors!
The saleable candy is so good that everyone wants it.
The saleable dog is the one that is the most friendly.