I'd start making your list of categories and then have associated linked words that appear in the title, where linked words are matched it's auto assigned a category. So Batteries (category) would be auto added to any product with battery, batteries, volt & discharge.

Just setting up some rules of how you would manually understand what a product is & automating it. Plus once you have good linking words to fit each category it should be perfect for new products that need categorizing. With MTurk, you'd have to keep paying every time new products were added.