Are there places where I can sell items for a higher price than the merchants?

Is there possibly a shop where I can sell materials and food for a higher price than regular merchants like Beetle? Or do they all offer the same prices?

There is no shop per se, but there are people that will buy your things for more money. This is not an exhaustive list, but any means, but some examples are...

• Fireproof Lizards can be sold to a guy in the mines to the south of Goron City. He'll first give you an item, and then will buy three lizards at a double-cost rate to what you sell them for to merchants.

• There's a guy in one of the stables that will buy your Gourmet Meat at 100 a pop, though you can only sell to him a few times a day.

• A Gerudo woman in Goron City will buy a random type of gem in batches of 10 for 200 rupees more than their normal sale price. However, you don't know which gems she'll ask for.

There is a Gerudo who walks around the Goron town. She buys gems at a rate higher than a shop, in chunks of 10 at a time. If you have a fair amount of gems, she's a great npc to visit.