Amazon offers Prime members the Rocketbook Wave Smart Notebook, model no. WAV-S, for $27 with free shipping. (Non-members can spend $49 or more to qualify for free shipping; otherwise, shipping costs $6.55.) That's the lowest total price we could find by $5. You can microwave it to erase and reuse up to five times, and it allows you to instantly store your notes on the cloud via Android or iOS app.