If the mempool is not full, then no fee is needed. If the mempool is full, then in order for your transaction to be included into the next block, you'll need to add a fee of at least 5 mojos per cost. The recommended minimum fee in this scenario is:
- Minting an NFT with a DID: 615 million mojos
- Transferring/selling an NFT: 335 million mojos
For other scenarios, see our NFT developer documentation.