Software to automate file grabbing via ftp, detailed manipulation and uploading result by sgodding

As a small business that retails on several online marketplaces (ebay, amazon.com, .co.uk, .de etc) through one portal who sends modified csv, txt files to all these venues in the appropriate format for the items to arrive at that marketplace with the correct price and description etc... (Budget: £250-£750 GBP, Jobs: Data Processing, Database Administration, eBay, Excel)