Cost is not even on my list of reasons to grow veg .
I don't think supermarkets can really be beaten on that score for most stuff , i want my food free of chemicals , but i can't afford to buy everything organically grown .
My land has never had chems put on it , ( i know the man who used to own it . He didn't put anything on it , nor did his dad . That covers over 90 years ) , so apart from what falls out of the sky , my own veg is very clean (chem free) and i eat it within hours of harvest , mainly .
So chem free , gm free and fresh , that's enough for me , although saving few £ would be good .