You can sand and stain your deck by yourself or get it done professionally. On a per square foot basis, sanding and staining can cost anywhere between $2 - $4. This cost should be inclusive of labor and materials used. Depending on the size of your deck this could be anywhere between $400 to upwards of $1000. An average deck will cost $700-$750 for sanding and staining. Doing this job on your own will cost you about the same as the lower end of this range. Around $400 or maybe less if your deck is smaller.