Siman 600

(157.) I heard in his name — one person told him that he had dreamed of fire. Rabbainu o.b.m. answered and asked him: "And what did you interpret for yourself?" He replied that he interpreted it for himself that there would be a good fair that day and he would earn money. Rabbainu o.b.m. replied: "Indeed — fire alludes to money — for keseph [silver/money] in its full spelling equals esh [fire] in gematria: kaf, samech, pay equals exactly esh."