Dream catchers can be brought and sold pretty much anywhere, as they are easy to ship and package. 67% of all dream catchers sold in the USA are sold online and that number is expected to reach 80% by 2020. The most popular choice for dream catcher purchases is Amazon. Although there are many different stocks and marketplaces in real life that actually sell dream catchers but these are usually the mass produced China imports with very little uniqueness to them.
However another place you can buy dream catchers from is Etsy which has some amazing (but expensive) dream catcher, they are totally worth it as they are all unique and hand made. Try Etsy if you do wish to see some amazing designs they will make sure that you are the only one in the world who actually has that dream catcher.