Source : Webster's Revised Unabridged Dictionary (1913)

Thriftily \Thrift"i*ly\, adv.
   1. In a thrifty manner.

   2. Carefully; properly; becomingly. [Obs.]

            A young clerk . . . in Latin thriftily them gret
            [greeted].                            --Chaucer.

Source : WordNet®

thriftily
     adv : in a thrifty manner; "a used towel that he had used and had
           left thriftily on the ledge below the mirror rather
           than consign to the linen basket"