Gonna need more info to give a definitive recommendation. What are you cooking? What material is the pan made of? Why can’t you use pam? Is it just the refillability that matters? Because if so then you can just use the same ingredients as Pam, which is mostly canola oil, coconut oil, and palm oil. You can also often use those oils individually as substitution, though the flavour and smoke point can vary for each so it depends on what you’re cooking and what temp you’re cooking it at. If it’s the lecithin in particular you want then you can use sunflower seed oil or add it to a mixture. I think Pam might also offer a non-aerosol version of Pam cooking oil that’s refillable if you wanna try checking out that route as an option.