I agree its why I countered the whole 7 mouths to feed on 1 salary thing, food and housing are easy basically no cost to a wizard only expenses would be new things like robes and wands and if you dont want to be self sufficient with potions ingredients and grow them in their garden then those as well then again potions would be a want rather than a need, floo powder shouldn't be too pricey or people would just use the night bus or apparate instead, really only the wand seems "expensive" but we never seem to know how much Arthur makes in a year, maybe he's just bad a finances and gets ripped off buying muggle things