Don't trade it in, some store like Scheels will screw the shit out of you
No, Scheels isn't going to "screw" you. It's generally a very transparent process. Granted it's been 20yrs since I've worked in a Scheels store, but, I'd show the customer the retail value of their proposed trade-in gun in the "Blue Book of Gun Values" which provides values from new in box down to 10% condition. I'd appraise condition and tell the customer what I thought the gun would sell for on our shelves and give them ~60%-80% of the retail number depending on how I supposed the gun would sell on our shelf and whether they were trading or selling outright.
There's a big myth that there's a ton of margin in guns. There's not, especially not in new guns.
ND, SD, MT, and MN easily have the least expensive guns in the US. We have WAY more competition per capita than the rest of the country. There's lots of places in the US where your only option for guns/ammo in a 50Mi circle is Wal-Mart. You get into any community of ~5K or more people in ND, SD, MN, or MT and there'll be 2-5 places to buy guns/ammo in town and 5-10 more within a 100Mi circle.