Theres profile info on them on this forum plus heaps on google, it doesn't really matter how cheap a fish is, its wether you tank is suitable for it or not that is the question.
looking at your other thread I would agree that with your stocking levels you dont have the room for glass catfish. If you seriously want them, or lots of other fish then i suggest you get a 2nd, bigger tank.
i bought 3 glass cats last week they hide in caves alot but last nite they were up feeding near top along with my widow tetras and danios im getting few more when my bigger tank arrives friday and its all set up i think their pretty cool,
hard to see when in a cave though was looking for the black head in a dark cave LOL dawned on me after few minutes it wasnt gonna work haha
but definately a talking point and an unusual addition to any tank
each to thier own i guess i admit the heads look bit ugly but when the light catches their body they shimmer like rainbows and my other fish seem to not notice em when feeding they almost bump into em especially the danios which zipping round tank anyway LOL