I have the 65 mm Vortex Razor spotter and have had it since early summer 2013. I use the Promaster 525 carbon fiber tripod and the promaster panhead. I used this setup on one mountain hunt so far, along with several trips to the rifle range. I have been very please with this setup. The tripod / head is plenty stable for the 65 mm spotter, and it weighs less than 3.5 lbs. It also packs down to under 19". The head is pretty good, not great, but you can find them for about $45 - $50. There are much better heads available, but they will be much more expensive. This setup is great for sitting, but is a bit short for comfortable standing. This Promaster setup is above your stated price range. I am pretty new at western hunting, but since you have a $1,200 spotter, don't skimp on the tripod/head. You will probably not get the full use of your spotter with a low quality tripod.
Good Luck