This tool will help you calculate how much space your Solana ledger will take up on disk.
If you don't want to run your own node, you can use o7 Node to get reliable, high-performance RPC nodes for your Solana projects.
To set the ledger size limit when starting your Solana node, use the following flag:
solana-validator --limit-ledger-size
This sets the maximum number of shreds your node will store on disk.