Sentence:  Thus the red damask curtains which now shut out the fog-laden, drizzling atmosphere of the Marylebone Road, had cost a <WSD>mere</WSD> song, and yet they might have been warranted to last another thirty years. A great bargain also had been the excellent Axminster carpet which covered the floor;nb.... 
Meaning of the word marked with <WSD> tags:  Just, only; no more than (from 16thc.), pure and simple, neither more nor better than might be expected.