Gillette regular is 2.49€ in big market. i can weight my bottle next time to see how much it loses stuff/shave. (if i remember)I don't believe that canned foam can be "cheap". My shaving brush is about USD 2 and should last 5 to 10 years or more. My ARKO stick also cost me USD 2 and that lasts me abou 150 three-pass shaves.
I haven't bought a can of foam for many decades so I have no idea what they cost now nor how many shaves they are good for.