While most advances can only be obtained by leveling up and spending an Advance Point to research them, some advances can be purchased using the in-game currency, credits. A nation starts with 250 credits, and more can be obtained in many different ways; for example by capturing and holding Orbs, completing quests, raiding, and defending your nation’s home island from raids.
To purchase an advance from the Advance panel’s list view, choose one of the advances in the second group in the list, “Available to Buy”. Most of these advances are temporary, and expire after a number of minutes or hours; click (or tap) on an advance’s line to bring up its info and see how long its duration is. A few purchasable advances grant a permanent boost to the nation’s stats (well, permanent until the nation rebirths; see Rebirth.) You can quickly tell whether each advance in the list is temporary or permanent, because a temporary advance will show a stopwatch icon at the far right end of its line.
To purchase an advance from the Advance panel’s tree view, click (or tap) on an available purchasable advance (which will emit an aqua colored glow) and press the “Buy” button. The purchasable advances that are part of each advance sub-tree (Tech, Bio and Psi) are listed in a column to the left of the rest of the advances in that sub-tree. Purchasable advances that are general and don’t require that any other advances have been developed before they can be obtained (but may require that a nation has reached a particular level) are listed at the far left edge of the advance tree.
The price of each purchasable advance is based on demand and changes daily.