Art is priceless, as long as you really like it, it's worth the price! I have collected many works of folk calligraphers, and the works that can be handed down from generation to generation are just some folk calligraphers who are obsessed with calligraphy and know nothing about secular affairs. So now many places like to collect some folk things!
Perhaps, your friend didn't pay so much money to get the work itself, so from this perspective, your friend earned you a little. If you are really good friends, I will give it to you!
Take good care of it. Don't use money to measure works of art, it will distract your attention from collecting this hobby and disrespect calligraphers!