We use Usage>Import. The user provides us a list of prices in Excel and we have a VB macro that creates the import file in the correct format. Then we run the Usage>Import utility and update the price lists.

We create the master price list in Excel and use the Import function to bring the file into X3.  We have multiple price lists (domestic, export, and customer specific)  After import to a custom table we use a process that we wrote to create the multiple price lists.