Cheapside, n. — Green’s Dictionary of Slang

Cheapside n.

In phrases

by way of Cheapside [pun on proper name Cheapside, a well-known street in the City of London. This name comes from OE chepe, a market, a place of buying and selling; although directly linked, the adj. use, meaning low in price, does not emerge until the early 16C]

on the cheap, at a bargain price; often as come at it by way of Cheapside or come home by way of Cheapside.

c.1786		Grose Classical Dict. of the Vulgar Tongue ms. additions n.p.: Cheapside. He came at it by the Way of Cheapside; he gave little or nothing for it.
1788, 1796		Grose Classical Dict. of the Vulgar Tongue (3rd edn) n.p.: Cheapside. He came at it by way of Cheapside; he gave little or nothing for it, he bought it cheap.
1796		Chester Courant 17 June 1/2: Cornelius O’Crotchet’s Description of Longman and Broderip’s Music Manufactory in Cheapside, London. Having heard a great buzz about Longman and Brod’rip, / [...] / Just only to take a slight squint at their shop: / But, oh! thunder and ’ounds, / What a bodd’ring of sounds, / Echo’d thro’ the whole building. / Blood and turf! he’d look back, / One of Longman’s grand forte-pianos to hear. / [...] / And suppose we should sup where we dine, / Why, ’tis all by the way of Cheapside!
1811		Lex. Balatronicum.