Well she got most of em for free via gifts (ironborns) or intimidation (master's). If she have to pay the crew, I assume high garden, dornish and her own money will keep them fed with iron born running ship maintenance.
Now if we want ridiculous it will be the amount of knights the vale can field in battle, all mounted, heavily armoured and as numerous as the boltons. Even at the height of their powers, the Byzantines, French and Holy Roman empire could only maintain a 1 to I say 100 ratio of heavy cavalry to other units because of the expenses needed. Either the vales is filthy rich or everyone doing public services like the Mongols and the Romans.