I haven’t found any serial number but Thank you for the infoUnfortunately it probably isn't worth much unless it is made by a really well known maker and is collectable. This style of saddle makes me think it might be from the 80s and the people looking for something that old usually want it because of who made it for a collectable item or are looking for a really cheap saddle.
Your best bet is to look for identifying marks somewhere on the saddle and search specifically on that. Check the back of the cantle (the seat) for some kind of makers mark. Serial number will be on there somewhere. If they are still in business you can call them and they should be able to look it up and tell you a lot about it.
I check everywhere but still didn’t find any serial number or marks Thank you for leaving a comment it means a lotAre there any markings like a serial number or brand? Maybe look under the fenders or underneath? It really depends on what type of saddle it is, how old it is, the wear on it, the brand, materials and so on to price it. I had a saddle kind of similar to that one(it was given to me by a friend who didn’t have horses anymore), and I couldn’t figure out a price for it so I sold it for $100 at a local used tack place. Another option could be putting it in a tack auction if you have any of those around your area another option is to search around the internet for similar looking saddles and see what they sell for! Good luck with selling it!😊