Inventory and COG tracking software or sheet

Hi. I am reselling on Ebay and Amazon and often buying multiple quantities (i.e. over 200) of same item. I am also sometimes selling items in bulk/sets. I am trying to find the best way of accounting and keeping track of these. I’ve been using Reseller Spreadsheet 2.0 (as well as different spreadsheets) but all require multiple quantity items being listed in a separate line. Do you know of any spreadsheets or software (possibly free) that would make it easier?