i've purchased from deepdiscount.com , while they are cheaper most of the time, sometimes amazon.com with their "secret" sale is cheaper.
secret meaning, you only know there's a sale when you click checkout on your shopping cart.
like the time I ordered flight of the phoenix at deepdiscount thinking they were cheaper by two bucks. but amazon.com (where I bought my other blu-ray discs was more expensive by two bucks each BUT, when I clicked checkout, they were having a 4 for 3 sale)