We all give in to temptation occasionally, but--really--bad idea to buy a living creature without knowing how to care for it.
Biggest issue people generally run into with these is their shyness. They really do need to be in larger school (6+ minimum, a dozen or more would be better) to feel secure in a species only or very calm community tank and should be watched carefully to ensure they're getting adequate food. They do best with lower light levels, live foods and absolutely pristine water conditions. Between needing to ensure they're feeding well and a proclivity for bacterial infections, a quarantine tank is *highly* recommended. Otherwise, moderately soft water, neutral ph, the usual 70-80 degrees, with some sources recommending as high as 82.