Ebay, Amazon/Amazon Japan, r/gamesale, your local game store, whatever buy/sell app is popular in your local area.

Amazon you need to look at the regular listings and then click the "New and Used At X price" button on the listing. "Renewed" is their refurbished line from third party sellers and that gets priority in Amazon's searches.

For example here's a n3dsxl page and here is an LL listing.

You can also look on ebay and compare prices , seller reviews, etc...

https://www.amazon.com/gp/aw/d/B00S1LRX3W/ref=mp_s_a_1_1?ie=UTF8&qid=1468335113&sr=8-1&pi=SX200_QL40&keywords=new+3ds+xl&dpPl=1&dpID=41ocgMxqDeL&ref=plSrch

http://www.amazon.com/New-Nintendo-3DS-XL-Black/dp/B00S1LRX3W

Ships from and sold by Amazon.com.

My launch day system was as well.

The black new 3ds xl is also up for $175 https://www.amazon.com/New-Nintendo-3DS-XL-Black/dp/B00S1LRX3W/ref=sr_1_1?s=videogames&ie=UTF8&qid=1470073251&sr=1-1&keywords=new+3ds+

N3DS

Yes they do