I am often asked, “Can I pay for an entire year of your classes up front?”  
I used to offer this option, with a discount.
Unfortunately, I no longer offer the annual payment option.  I was shocked by how many people took advantage of the annual payment option (with a discount) only to ask for a refund near the end of the year.  
I finally decided it was best to offer one option only… the monthly option.  This gives everyone the chance to join for a bit, test it out, and cancel anytime.