What's wrong with just getting them a fondue set, apart from that no one wants a fondue set....
I once wanted a fondue set, having used one at a friend's house. It was 1985.
In response to the question, I would never give money as a wedding present. I'd give a present. Something untraceable from a local shop so no one would ever know the monetary value. And I'd choose what to buy based on it being something nice and how much money I had at the time. (We've got a vast array of fantastic shops round here before anyone thinks I mean the local newsagents.)