In addition to the previous posts, I haven't had any problems selling
Coach on ebay and Tradesy (knock on wood), and have sold over 30 bags on those sites. I do accept returns on ebay (on the theory that as per ebay policy the seller is going to accept returns whether they like it or not, so I may as well be in control of it and charge a restocking fee), so I've had a couple of easy returns, and only one scammy one that got ruled in my favor on a bag that sold for less than $100. I don't ship outside of North America.
Prices are all over the place, depending on the item. As was said, the only way to get an idea of the best selling price is to check sold listings for that exact item, usually by searching on the style number.
IME, one gets a better price by always putting the style number in the title and always having good photos, especially a clear creed pic in the listing if there is a creed in the bag. If you have a small piece over a year old (about the time they started sewing paper tags in the pockets) without a creed and you don't know the item name or number, the ladies in the "ID This Coach Item!" thread are extremely knowledgable and helpful, even if you're a seller, because they want to see correct information being spread. Good luck with your sales!