notso depends what I make but yes, usually. For example I can make a batch of American style cookie dough for about £2.50 that will make 30 odd cookies, like the ones or you get five for a quid 'fresh baked' ones in the supermarket. I tend to use half the dough and freeze the rest, things like biscuits keep well for a week.
Also, I make cakes that are meant to be kept, such as Nigella's Clementine cake or a Madeira cake. In the olden days, people used to make a cake on a Sunday and it would be kept as nibbling for the following week. Fruit cakes are another obvious one that it is far cheaper to make and lasts for ever. I know all this, boringly, as I occasionally make them for other people so have to price them against the supermarkets.
Another tip - ignore the silly chefs, don't bother using pricey fancy choc for baking, it really doesn't make a big enough difference to justify the cost. 200g bars of dark choc from Asda for £1.20 is far far better!
BUT the exception is that as I usually cook mostly from scratch, I always have flour, baking powder, vanilla essence, eggs around so it isn't a big deal. I expect if you had to go out and buy all these things specifically for one thing it would be pricey.
The only thing I don't have in is chocolate, wouldn't last a minute!