I was talking to a designer this morning and he suggested 3 timber frame trusses with rafters inbetween creating a 24x30' pavillion. That would give me the nice vaulted ceiling look I want and probably be more economical.

You're right I did not address what the walls would cost, my example was just comparing trusses, not the whole structure.

The problem with figuring out how much money or time I want to spend, is there is NO easy way to figgure out how much it would cost me to do myself. After a few days of poking around the internet I found two places 2 hrs away that would sell me timber only and it will probably be a few more days before I get pricing.
Carter Lumber quoted me about $85 each for 8"x8"x10' lumber.

When I first started this project I naievly thought I could download a sample plan, callup a lumber store and get a ball park idea of what it could cost me in materials in a day or two. Afterall I have seen this type of structure at every state park I have visited for my entire life. It is such a common structure, however just because it is common doesn't mean it's easy to make!

Currently I am waiting for my book to arrive to get the sample 14 plans.

Perhaps I should start a new thread of where to buy lumber that seems to be the biggest hurdle for me.