Please check my sentences.

Dear teachers,

1. I am calling you to help you save money on your gas and electricity.

2. I am calling you to help you save money on your gas and electricity by choosing a cheaper supplier in your region.

3. I am calling you to find the cheapest gas and electricity supplier in your region and help you save money on gas and electricity.

4. The best part of this call is, we do it for free. You do not hae to pay any charge but we get a commission paid by the supplier.

5. The best part of this call is, it's a free service. I mean we do it for free for you but we get a commission paid by the supplier.

Thank you.