The suffix -less means not having ______
- A useless thing is something that doesn't have a use.
- A homeless person is someone who doesn't have a home.
- Something worthless does not have worth - in more natural English, it isn't worth anything.
So in our picture, the bags of rubbish, the broken umbrella, and the dead fish are all worthless.
Something that is worth a lot of money is very valuable, so you would expect to pay a high price for it. But for something completely unique, like the vases in the top-left picture, or the helmet in the bottom-right, are even more valuable than that. In fact, they are priceless - they are so valuable that they do not have a price. A synonym for priceless is invaluable, which means that something isn't possible to value, or decide the price of in money.