Found 2 items, similar to costless.
English → English (WordNet) Definition: costless costless adj : costing nothing; “complimentary tickets” [syn: complimentary, free, gratis(p), gratuitous]
English → English (gcide) Definition: Costless Costless \Cost"less\ (k?st"l?s; 115), a. Costing nothing. [1913 Webster]