Pixels

Pixels are the main currency in Starbound. It can be used to buy items from merchants, and you get it from selling items.

Normally you would get 20% of the item's pixel value when you sell an item, or 30% when selling via Terramart Shipments. However, different shops and merchants (especially shops on spacestations or vending machines) may have altered buy/sell prices. Most liquids, most blocks (like Dirt) and some items will cost 0 pixels (so selling them won't give you anything).

It's not possible to carry more than 1 million of pixels (anything beyond that will be lost), but you can craft items like 10k Voxel to store them.