Please take a look at the explanation on the DAWN release notes here:
https://pura.one/pura/

...the ROI of MNs are variable and the sooner you start-up a MasterNode, the sooner you will accumulate PURA, which once the price rises from simple supply and demand forces of economics your early days of earning block rewards from running MasterNode is going to become very very profitable.

How to setup a Masternode:
https://www.youtube.com/watch?v=fjK_8Up_plU&feature=youtu.be