You want new carpets? My brother-in-law can get them on the cheap from a friend of his.

The store is selling all of its merchandise on the cheap as part of its liquidation sale.

economically; at very little cost

We're travelling around Europe on the cheap.

(informal) for less than the normal cost (and therefore of poor quality)

He got it on the cheap so I wasn't surprised when it broke after a couple of months.