I'm an avid online shopper and have been for a few years. I have never found any other website with so much choice and variety of products at better prices than eBay.
A few top tips when purchasing on eBay:
1. Select 'free postage' items on the left column
2. Be specific in your search for items
3. List them lowest price postage first then browse
4. Select an appropriate price category
5. Just because it's international doesn't mean it will cost more, especially for free postage items!
I have better luck buying brand new items on eBay than second hand ones. EBay owns gumtree, and eBay is set up to promote new items more so than second hand ones. Although I have found a few great bargains from local seller for second hand household goods. In general, second hand items are better off found on Gumtree.