that board is worth $0.00.... no way to tell how long its been split like that but it looks like its been a while. it also looks like the core has swollen from being waterlogged. if it is its rotten.
to be clear: if you did damage like that to a board you were riding it is repairable with epoxy and clamps, but you need to make sure the board is nice and dry inside.
if the owner of that board rode it on a few wet days with it split like that it could be enough to get enough water into the core to ruin it.
would not buy.