Tough call as you can guess alot of variables.
This kind of topic has been discussed extensively on this forum under variouse sections I think mainly in marketing or something like that.
Obviously if you wanna make sure you atleast make money you need to take the price of all your stuff that you put into it, seat pan, leather, thread/lace, dye, sealer, oil.......
then find out honestly how long it takes you to make it and try to figure out how much you wanna make an hour doing it.
Plus if you will be regulated by where you sell it depending on what poeple think they should pay, by how good of work you do, if you have a established name for yourself, is it custom work, so on and so forth.
That being said I have scene prices ranging from complete crap at $50 on ebay on up to several hundred dollars and more.