California sales tax:
I story I recall hearing is that California enacted the sales tax during the 1930s. Initially it was only a sales tax and a number of people realized that they could buy their car, etc in Reno or Yuma and avoid the sales tax. The next year the State made it a sales and use tax so that if you bought something outside the state and brought it in right away you would be charged the use part of the tax.
Now this did not apply to an item that you used outside the state prior to bringing into California. So the railroads took delivery of their locomotives, etc. outside the state and used them there until the use period was up.
In the last years of the independent SP the business equipment and inventory taxes were a reason that the SP was looking at establishing a main locomotive shop in Sparks, Nevada.
Many businesses, like JC Penny, maintain regional warehousing in Nevada and then ship into California to avoid paying the California inventory tax. Also the annual inventory tax is a reason for the inventory reduction sales.
Brian Norden