In this case, there is no cap on the number of tokens being sold, and the sale runs for a fixed time. The exchange ratio can either be constant, or changed as the sale progresses. A common form of this sale gives better rates to early contributors, with the rate decreasing as the sale proceeds. This mixed-ratio scheme is similar to how the original Ethereum ICO was run.

The schemes presented thus far have involved a simple token purchase at a given price. Auctions are a form of sale that are more interesting.