If of all the Fuji X system cameras it is the X-T1 body only the one you want, it is currently available in used condition starting at $630 at B&H Photo with free expedited shipping. This is a Condition 9. They also have higher and lower conditions. Make sure to check under the “In the Box” section for each individual used listing to see which ones of the original accessories are included. The included accessories affect price and you may or may not need them depending on what other accessories you already have.
Used products sold at the B&H Photo website come with a 90-day warranty from B&H Photo, not the manufacturer.
On the other hand, if you prefer refurbished, and want the 18-55mm F2.8-4.0 lens as well, the X-T1 with 18-55 kit is offered in Certified Refurbished condition by Dealfisher fulfiled by Amazon for $855~ with free shipping. Since it is fulfilled by Amazon, it is Prime eligible, and it ships from Amazon’s warehouses, which makes potential returns and customer service more streamlined since you deal with Amazon, not the 3rd-party seller.
Note that “certified refurbished” is an Amazon term as it refers to products sold on their website under the “Certified Refurbished” banner. Among others things they offer a minimum of a 90-day warranty. This is Amazon’s Help Page on certified refurbished. And this is a listing of Certified Refurbished products on their website.
Note also that “certified refurbished” does not necessarily mean “manufacturer refurbished” in Amazon’s “certified refurbished” context.