I've been looking for a "cheap" CPL filter, by that I mean I don't want (or can afford) a top quality one such as a Hoya Pro. I was hoping to get a reasonable used one for around £20, however I've seen a Haida 72mm at Premier Ink for £7.70!!, can this possibly be any good? I'll probably only use it a couple of times so the price certainly appeals to me but I don't want to throw nearly eight quid away if it's totally no good when I could put it towards another one. Anyone used one?