Do you pay all at once, or at the annual rate each month? Are there any cancelation fees?
Salesforce does not have per-month pricing; all of its plans require an annual commitment. You pay the price listed times 12 when you start your subscription, then will pay again next year when your plan renews. If you want to cancel Salesforce, be sure to contact their sales department more than 30 days before your plan renews so you're not billed for the next year.