I've a very unrefined palate - peanut butter is peanut butter as far as I'm concerned, so I'm quite happy with the Tesco value stuff which is not only less than 70p for a decent size jar (compared to £2 for a smaller jar of the Meridian stuff), but is also, importantly, lower in carbs than most posh peanut butter despite having added sugar. Turns out that oil is cheaper than peanuts, so the value stuff tends to have a higher oil content which suits me fine - you just have to store your jar upside down to ensure the oil doesn't all congregate at the top.
Of course, you could also make your own - blender, bag of peanuts, some groundnut oil (rather than the veg oil everyone else uses) and then any seasoning of your choice, job done.