Yes, Walrus provides a TypeScript SDK that you can use. It's developed by Mysten Labs and it supports a wide variety of operations related to Walrus. You can find the SDK here. They are also working on a Rust SDK for Walrus, which will be available after the Mainnet launch.

Regarding storage payment, Walrus uses a native token called WAL for storage payments. At the end of each epoch, rewards for storing and serving blobs are distributed to storage nodes and those staking with them. WAL also has a smaller unit called FROST, where 1 WAL is equal to 1 billion FROST. Payments for blob storage are denominated in WAL tokens, specifically for the Testnet version which uses a Testnet WAL token issued on the Sui Testnet. This token has no actual value outside of testing purposes.