Value/worth is dependent on the amount someone is willing to pay for them.
One day they might be "worth" $200.00 and another day they might sell for $100.00.
It's not an exact science.
do these signatures look good to you?
can you check this one for me
Those are PSA/DNA Auction LOAs, which are similar to what PSA calls Auction Pre-Certification today. They are not full certification. The only way you to tell if the LOAs were for the autographs you bought would be to go back to the auction's catalog and match it up.
The autographs do look real, though. Nice examples of both.