These are the rates that Gauss will exchange recognized favors for within the community For example 30 Gauss favors gets you a Militia favor. A favor usually works out to about a day’s work for the person that issued it but there are exceptions, notably Gauss favors themselves. In the future you will be able to see what a favor buys you with a character on their character page.
To trade favors with someone you lay out the terms and then shake on it. The Exchange then recalculates, accounting for the transaction. If you want to sell your own favors, Gauss will set your initial price after a painstaking review of your deficiencies.