Two buckets (or jack stands) and your axle is all you need. Oh, and gravity.
Just slide your axle through the wheel and set it on the stands. Use your fingers to twist the axle back and forth to break the stiction in the bearings. That will work plenty well to get your wheel balanced. It what I use on my 9'r, by 600 race bike and friends bikes. No one has ever felt a vibration.