εἰργάζοντο λογάδην φέροντες λίθους καὶ ξυνετίθεσαν ὡς ἕκαστόν τι ξυμβαίνοι → they went to work bringing the stones as they picked them out and put them together as each one happened to fit
frugally: P. φειδωλῶς.
cheaply: P. εὐτελῶς (Xen.), μετ' εὐτελείας; see cheaply.