Hi. I bought my Sixer from ToucanHobby via AliExpress. (They have their own website too). Many other AliExpress stores carry them too, but I'd always exercise caution navigating the murky waters of online marketplaces. This is especially true of AliExpress.

In retrospect, I probably should've bought mine from Kaioz.net, which is where I'm actually buying all the options and upgrades for it. The reason I initially hesitated buying it from Kaioz was because the store doesn't list prices outright. Instead, you add items to the card, make an inquiry, and they email you back with the total. My experience with them has so far been positive though.

Let me know if you have other questions. (Note that I am not affiliated with Kaioz in any shape or form).