mix and match
1. to assemble a limited number of items, usually clothing, in a number of different ways. Alice learned to mix and match her skirts, blouses, and sweaters so that she always could be attractively dressed on a limited budget. Gary always bought black, blue, and gray trousers and shirts so he could mix and match without too many bad combinations.
2. to select a number of items from an assortment, often in order to get a quantity discount. (As opposed to getting a quantity discount for buying a lot of only one item.) The candles were 25 percent off, and you could mix and match colors, sizes, and length. I found a good sale on shirts. They were four for fifty dollars, and the store would let you mix and match.