All of the Internet Sellers I buy from (including Amazon and Tire Rack) add California sales tax to my purchases. But I'm moving to Portland in a week-and-a-half, so that's the end of that---no sales tax in Oregon! The State makes up for it in higher property taxes.
Would you be more likely to buy new gear out of state if there was no sales tax
There is a retailer that advertises in the Absolute Sound that you can buy gear from him without paying sales tax. He is located in Delaware where they don't have sales tax. Being from California that would save me 9.5 percent off the top and that is without even negotiating. I don't know if he charges for shipping or not but it seems like it could be beneficial.