Best buy are products that are easy to ship (light, small), which are difficult to find in the local market (especially second hand, rare), which are too highly priced locally, and where you can assess the quality over the web.For example, I bought high quality used lenses for my camera. I also bought rare stamps. Also clothes and shoes (new). I did NOT buy furniture, nor cars, nor real estate.
Skincare, perfume, clothes, dvds are cheaper there which is appealing. You can search for the post popular items on ebay pulse.
CDs! Great place 2 get rare promos :L