ASOS is a great site to buy jeans as they offer a huge selection of brands as well as free international shipping. My dad found a pair of Pepe jeans on ASOS that were about $50 cheaper than the prices at our local stores.
Blue in green, selfedge the way to go. If you want something closer to home in case of taxes and stuff you can try the denim store and tuckshop and sundry suplies. If you already know what fit you're looking for and what size you need I would advice to order from rakuten because it's a lot cheaper now because of the weak yen so you could get a pair of expensive japanese denim for like $200
There are so many online denim shop available where you can find your desirable denim. you can simply search in any search engine and you will find a lot of website about denim. Here is a website where you can find different denim items http://www.jazzylook.com/search/label/Men%27s%20Jeans