What I always do for lagers is use about 1/3 package of a "clean" ale yeast- like nottingham. I mix up my priming sugar/solution, and let it cool then stir in about 1/3 package of the dry yeast. Then I rack the beer into it. It works great, and the beer carbs up nicely at room temperature in about 2-3 weeks.
It's such a small amount of yeast that I wouldn't spend the money on liquid yeast, and the flavor isn't impacted at all.