The Collaborative International Dictionary of English v.0.48:

Thriftiness \Thrift"i*ness\, n.
   The quality or state of being thrifty; thrift.
   [1913 Webster]

WordNet (r) 3.0 (2006):

thriftiness
    n 1: frugality in the expenditure of money or resources; "the
         Scots are famous for their economy" [syn: economy,
         thriftiness]

Moby Thesaurus II by Grady Ward, 1.0:

26 Moby Thesaurus words for "thriftiness":
   austerity, austerity program, canniness, care, carefulness,
   chariness, economic planning, economicalness, economy,
   economy of means, false economy, forehandedness, frugality,
   frugalness, good management, husbandry, management,
   parsimoniousness, parsimony, providence, prudence,
   prudential administration, sparingness, thrift,
   tight purse strings, unwastefulness