I used to wear long underwear under shorts while skiing. This worked pretty well, but I would get a bit cold when I stopped for lunch. Then I bought a pair of full zip fleece pants. A bit heavier, but way better range. If it is hot, I can open them up or completely remove them (without taking off my skis). If it is cold, they are way warmer than tights.
When hiking, I find that I need them less. Most of the time I hike, I hike in shorts. So, my pants stay in the pack. However, when the weather gets bad, or I get to a summit, then I switch to either rain pants or wind pants. Both are lighter than tights.
I do think tights are fairly economical, though. You can get a good pair of polypropylene long underwear (AKA tights) for very little money. This covers a pretty wide range for very little money. When combined with a wind/rain layer, they also provide plenty of warmth. The biggest cost at that point is in terms of weight (puffy pants are lighter). They also make sense if you are sure that your trip is going to fall within this sort of temperature range -- personally, I rarely hike at that range very long.