One other thing to note I forgot to mention is to pay particular attention to the genus and species you are ordering. Most of the colorful dwarf shrimp you'll see offered are color morphs of either Neocaridina Davidi or Caridina Cantonensis. While you can safely mix any of these together, be mindful that if you have different colors of a single species, the juveniles won't be a combination or mix of the two colors the parents were: the line-breeding reverts back to wild coloration (clear and brown, mostly). The neocaridina shrimp can't breed together with the Caridina shrimp, but Caridina what-evers CAN hybridize with Caridina what-cha-ma-haves (same with Neocaridina).
Some popular names you might find Neocaridina shrimp listed as are Red Cherry, Fire Red, Sakura, Blue Velvet/Pearl, Yellow, Snowball, or <insert color> Rili Shrimp. Unless you're looking to impress other shrimpers, there isn't anything that inherently makes a Fire/Painted/Sakura Red shrimp superior to a run-of-the-mill Red Cherry Shrimp, they just cost more due to varying coverage and opacity levels of the line-bred color. Myself, I prefer the red ones with clear marbling I seem to keep hatching (these are also trash grade as far as many are concerned).
Some popular Caridina shrimp include Red Crystal, Black Crystal, Tiger, and Bee. The same thing with adjectives and prices apply here, as well!