Exporting all items
It is possible to export a complete list of all products in a format which is ready for updating and re-importing at Settings > Products/Inventory > Price lists :
Exporting a price list
Alternatively you can export just one price list to Excel or CSV. A specific price list export will list each product which has a price on that list, even if it is zero (where prices are blank, the product is not exported):
Exporting a selection of products
You can use the filters on the product list to export only a subsection of your products. By default, only one price list is shown on the product list - it's the one that is set as "default price list for new customers".
Change the price list(s) shown using the filter section.
Note : if you're exporting from the product list, any price lists set to "show including tax" will have tax or VAT added, and if you are going to re-import you'll need to ensure your prices are all excluding tax.