Do I need to pay for a year upfront?

No. Most of our customers (75%+) pay annually, but you can choose to pay monthly as well.  Usually by the time a customer signs up they are comfortable that this is the right solution for their company.  One annual payment is easier for expense reports.  And we offer a discount for annual payments!  

However, we also have a monthly option -- the prices are 20% higher per month, but you can cancel at any time.