I have been there lots of times....well through every year and also a few times to stay a week. I have no idea about prices, as we were "tourists." It has lots of cool stuff to do ( as tourists.) It's on the dry side of Oregon (east of the Cascades) So it's fairly flat, and very agricultural as far as the look of the land. We have been tempted to go that direction someday even though we are native wet siders!
Climate wise it is hot and dry in the summer (100+) usually for a couple of weeks, and below zero isn't uncommon in the winter. Pendleton proper has a winter polution problem because it tends to get inversions.
Most things grow if you just add water and it has a large farming community. In the summer wind and dust storms can be a problem. Wheat and potatoes are the most common crops.
I lived there for a few years. LOVED IT! You have to see the underground tour... it is incredible.
Regarding houses and land prices. I'd say pretty spendy. There's a few realty's there... century 21 and Gartons'. You can go to the newspaper.. It's www.eastoregonian.com. Land in the surrounding areas could be cheaper. Hermiston isn't far, smaller communities like Athena and Weston arne't far out either.
Depending on your income, you can check with the rural development also.