Where to buy the Acekard 2i for DSi XL

Where can i buy the nds xl card Acekard 2i with 2 gb memory?

 

There are hundreds of shops selling the 2i. Here's one that I trust because it's the official sponsor of gbatemp.net (the largest NDS mod forum):

http://shoptemp.com/products/Acekard-2i-Card-for-Nintendo-DS-DS-Lite-DSi-p-30.html

^That just means you have to download a file from the Acekard website and boot up the 2i in a regular DS before using it on an XL.