I agree with what has been said so far and I'd like to add a usability component. I first separate tripods into two categories; packable and base camp. Here are a few things on both categories.
Packable: I think you can find a good packable scope for $100. At this price you can get a durable tripod that is somewhat small; however, it will be larger, weigh more, and extended height might not be as tall. In the $100-$200 range I think you can find a smaller, lighter tripod that will extend higher. $200+ I can't speak about because I haven't used any or found any in stores.
-With all these scopes I haven't felt a small tripod can handle a 80mm spotter, usually because the head is small. I use a ball head and it definitely doesn't work well with a big scope.
-Scopes below these price ranges are usually lacking in the durability area. I have known of multiple people buying $50-$100 tripods that have to replace them the next year because the plastic ends up breaking (number one thing to look for-no plastic).
Base Camp: Most anything below the the $100 price will have durability issues. there are some out there that are more durable; however, they usually do not have very good leg extension-they are short. Short tripods do not work well when look through a scope while standing. you end up having to extend the neck and the picture becomes less stable. $100-$250 as mentioned by BB not all scopes will be good in all areas and this price range has a lot of this issue. Scopes will start to be more stable (not all are equal) usually quite durable but they are usually too heavy and you can find tripods with better heads.Some will be limited in height and there might be something just a little off about the head.$250+ Very good stability, height, can be lighter, and I have found this is where I really start to like the head-usually real smooth and able to hold position well when you stop while panning.