Are signed prints worth anything?

Similar to other artwork, hand-signed prints are more valuable than art that hasn't been signed by the artist. Where the signature is located does not have an effect on the value.

Yes. Prints may not have great value, but it increases if they are signed by a renowned artist. But other factors also play a role, such as a limited edition and one-of-a-kind. If a large number of people have a work, the exclusivity and therefore the value are reduced.