I have a gallon size can of Berryman's Chem-Dip. It has 96 oz. of cleaner and not 128 oz. because the can would overflow when dunking parts in the basket. The can is 5 years old and has has been used many times and is still good.
A spray can is used until it's empty and you buy another can, I have no idea how many spray cans I would have used by now, but I do know dunking is more effective than spraying.
My dunking can has cost me $6 a year so far and cost per year is dropping. In another year, $5 and a year later, it's down to $4,25.
What I'm saying is don't be put off by the 30 bucks a can. Also Walmart carries Berryman's for less than $19 and if the local store doesn't have it in stock, free delivery to the store only takes about 3 days in my area.