Source, in full
The Proverbs of John Heywood, pt. 2, ch. 9, p. 162 (1598, reprinted 1874, 1978). The idea that if you spend a thing you cannot have it goes back much further than Heywood's original 1546 work. Plautus wrote c. 194 B.C. in Trinummus (act II, sc. iv, l. 414), "Non tibi illud apparere si sumas potest" (if you spend a thing you cannot have it), translated as "You cannot eat your cake and have it too" by one Englishman. Comedies of Plautus, trans. Bonnell Thornton, 2d ed., rev., vol. 2, p. 29 (1769)