How does Gnosis Safe make money? Are they charging fees for each transaction or just from opening a multi-signature wallet?
Safe is completely free to use, except gas fees from the corresponding blockchain.
The constitution proposal includes a principle to define and preserve the Safe protocol as a public good.
There are early conversations around token design and token utility. One of them has recently been published as a proposal which you can see on this page listing all proposals with the tokenomics tag: