1) clay costs 25
2) plan B (Get a +5 Gold pay raise for every half a year)
Lets starts by assuming that the red bottle is false (made by menes), which means that only one bottle or less can be false. Since we have the red bottle as a false, the yellow and blue bottles are true and we have no solution. This leads us to the conclusion that the red bottle is true, and if the red bottle is true the yellow and blue bottles are false. If the yellow and blue bottles are false then the cure is in neither of these bottle, which mean that the cure can only be in the red bottle.