If you follow the FN Production schedule, when they are in mil production, the public market dries up and prices skyrocket... once they stop and go to civilian production, the prices drop and stores have inventory. Check the bigger local spots like SGC, Tombstone Tactical, etc and see if they have scars on the shelf. If they do, you can bet others do and then you can make lower offers. If you cant find any, they are likely going to demand retail or better, knowing someone will pay for it, which they will, and have since they came out.
"Off peak" price is usually about $2400-2600 for them, $2600-$2700 would be a great price if you got the trigger and $40 a piece mags with it. I believe MSRP was raised as I havent seen them much under $3200 new when in stock anywhere, especially for FDE which does fetch a premium.
Edit, here's a FDE one for $2500 with Timney trigger and extra mags.
https://fnforum.net/forums/fn-guns-fn-items-sale/218927-scar-17s-fde.html