Butter - I've got lovely stuff at home with sea salt crystals in it. Be blowed if that was going to be used for kiddie cooking rather than savoured on toast. We bought the cheapest in the store, Sainsbury's salted a snip at 85p
Sugar - Enough to induce diabetes. Both soft brown and icing varieties. Don't even think that you've got plenty at home. We didn't get much over from either packet.
Peanut Butter - From the Sainsbury's basic range. It was 65p a pot. Crunchy of course. I can't fathom out why anyone would choose the smooth stuff.
We had vanilla essence and milk at home. The total cost was probably less than a teeny bow adorned box would cost at one of those fancy places.
The recipe was easy-peasy, a doddle for a child to make, and can be found here. I was surprised it didn't call for a sugar thermometer and had been perfectly prepared to be buying one as a long term investment. It needed longer in the fridge than the hour stipulated though. I'd give it overnight if I were you. Once the top of the fudge was set I tipped the slab out and turned it to give both sides a protective air-dried crust.
Here's the result made with about 2lb sugar. This is after we'd given rather a lot away and there was still masses left yesterday morning. The pile has gone down a bit now. No wonder. It's delicious!