DIY carbon filters

i know there are a lots of different DIY carbon filter ideas... has anyone made one? do they work? how long before they need to be replaced? or should i just drop a stack on a Charcoal Fiber Filter?

drop the stack if you gots it.....worth every penny of assurance no one will smell what you got but you.....otherwise go buy alot of activated charcoal...pet stores carry this....then get a five gallon bucket with a lid....drill mass holes allover the sides....the holes have to be small...then buy a flange that fits your fan and put it on the lid after you cut the whole out in the middle of the lid...attach you flange, ducting, and fan and you are all done....good day

how long does it last before it has to be replaced. around how much does your system cost?