It depends, but the average for your area would be about $1,200 to $2,000 a month. The size of your home matters as well. As you could imagine, a 10,000 square foot home would cost a lot more than a 2,000 square foot home.
The best thing to do is to first hire a great real estate agent, one that is experienced in staging homes, and then ask for their opinion. They will likely refer you to a staging company at a discount since they hire them frequently.
At UpNest (http://www.upnest.com) we've helped a lot of San Jose sellers save money if you haven't hired an agent yet. Top agents will compete to earn your listing. When agents compete, they are more likely to lower their commission rate. We can also make sure that the agents that submit to you are experienced with home staging!