DS has skied since toddlerhood, but then my brother is a snowboard instructor, and we lived in Canada until DS was 2.5 so spent a lot of time doing snowy activities. We go once a year, given the option I’d go twice but we can’t afford to currently (mostly because we are tied to school holidays).
He also plays rugby, because we did Rugbytots, and that was because when we tried the football equivalents, they were full of very over-invested Dads shouting at their toddlers. In contrast Rugbytots was fun and there was no pressure to do anything or be any good at it. He spent quite a lot of the first term sitting on my lap. Moved up to the local club when he was 6, and as a pp says it is a very cheap hobby - subs are £22 per month. Boots/kit are secondhand, they have a resale table in the clubhouse. He does also play football now he’s at school.
He plays tennis because he asked to. We used to knock a ball around in the park during lockdown (when he was 3), and he enjoyed it, so he did some tennis holiday clubs in reception, and still enjoyed it, and so we started proper lessons when he was 5.
We’re middle class but I don’t think we are particularly posh, we live in a two bedroom flat, DS goes to a state school, etc.