Farmers give the network information on the safecoin per GB by supplying or withdrawing storage space depending on what the network is currently offering (safecoin per GB). if the network needs more storage then it increases the safecoin it pays to farmers and that signals farmers to provide more storage.
But the value of SafeCoin is indeterminate from that information. It’s not linked to the value of storage space it’s linked to the value that people ascribe to SafeCoin - if the coin is popular and hence has a high value (globally) then farmers will provide more storage for less coin, yet not less value from the network.
The value given to farmers per GB (by the network) will always be related to the cost that farmers have to pay in value. But the value of Safecoin itself floats completely freely based on global use and perception.