According to where I got the recipe from you save money, I paid about 24p for Hair Conditioner (Value one, however you can buy fragranced if you wish for about 80p), I paid £1 for 500ml Vinegar from Wilko, but I needed all of it. Get a bottle & I put all of Conditioner in (400ml - 500ml), add all the Vinegar, top up with 500ml water (warm) then stir until there's no lumps. You just need to shake it before each use though.
However, advantages are that it saves you money & softens clothes with a fragrance of your choice because you choose the fragrance. Alberto Balsam is a great range to choose Conditioner from, you could make Apple, Mandarin, BLueberry etc. flavoured conditioners, but last time I used the Everyday Value 24p one from Tesco which was good.
It is good for Sensitive Skin & does work surprisingly, so does making your own Washing Powder!