WordNet (r) 3.0 (2006):

discount store
    n 1: a sales outlet offering goods at a discounted price [syn:
         discount house, discount store, discounter,
         wholesale house]

Moby Thesaurus II by Grady Ward, 1.0:

31 Moby Thesaurus words for "discount store":
   boutique, chain store, co-op, concession, cooperative,
   countinghouse, country store, department store, dime store,
   discount house, emporium, establishment, five-and-ten,
   general store, house, magasin, mail-order house, market, mart,
   post, retail store, salon, shop, store, supermarket, trading post,
   variety shop, variety store, warehouse, wareroom,
   wholesale house