I use one or two of those pre-moistened towelettes to clean my bike every so often. I roll up them up after I'm done using them on everything else and pull it between the cogs while on the bike.
Otherwise I'd just take a old rag soaked in light lube and use that to clean it. Or maybe mineral spirits or WD-40 or similar solvent lube. I wouldn't waste money keeping a bike specific chain or cassette cleaner. But if doing so makes you happy, who am I to object. Unless you also tell me I have to do the same.