I used oxyclean for years, then started using PBW, and the PBW is far superior, IMO.
I brew ALOT, like 25 batches a year, and a 8 lb container of PBW will last me about a year. At $35-40 retail for 8 lbs, that's $3-4 a month for the industry standard cleaner. I wouldn't call that "expensive."
My club even did a group buy, and got 100 lbs at wholesale prices, and got it down to about $3.00 a lb, which is very comparable to oxyclean prices.