Appraisals cost actual money.

Better to simply take the book to a dealer and ask what they can tell you about it offhand. Don't ask for value, because it won't be 'real' anyway

It's not like Antique Roadshow where a dealer will gush and tell you it's worth 1000 and be actually fairly accurate. There's too much at play when a rare book walks into a book shop

Dealers will be helpful about the rarity and maybe history of the edition, but they won't blurt out values necessarily. It's too complicated a situation

For one thing, the seller may be looking to sell it and the dealer may want to buy it. So, let's imagine he book is worth $1000.

would a dealer say "it's probably worth around $1000 or so, I'll give you a thousand dollars". No. The dealer would not"

Would the dealer say "it's probably worth around $1000, I'll give you a few hundred dollars for it". No. Probably not. But the dealer is being fair, since he/she has expertise, expenses, etc.

Would the dealer say, knowing it's worth $1000) "well. It's not very rare. If you sure looking to get rid of it, i can give you a hundred bucks"? Sure

Thing is. You can't go to a dealer expecting a free appraisal (again, people use the word 'appraisal' incorrctly all the time. Appraisals are formal written and documented statements of determined value. And even acknowledging this, you still can't expect to go into a dealer to get a fairly accurate estimate if value and then expect to sell it to that person for anything close to that

Go to a dealer and say "i onow nothing about this. Can you tell me anything?" And then see what they say. Thank them, go home, and do some homework.

You have to decide if you want information about the book, or to sell the book. The dealer won't do both for you (tell you the value and then buy it for that price)