what is the most basic puzzle i can start with?
You can start with 71, but please be aware that ALL PUZZLES UNTIL ABOUT 86-87 SHOULD BE WITHDRAWN WITHOUT USING PUBLIC BTC MEMPOOL. USE SLIPSTREAM SERVICE OF MARA POOL TO WITHDRAW SUCCESSFULLY.
And what's the plan for your $100 challenge? Gonna play it with MaraPool's slipstream, or rolling the dice with a regular mempool transaction?