Yes anytime to the end of a billing period. A billing cycle is one Month.
Cancel your subscription in your Dashboard in the billing area.
Once you have canceled we want bill the next period anymore.
Payment can be made via credit card (Visa, MasterCard, American Express, Diner's Club, Discover) Bank Transfer through SEPA Network is for European Enterprise clients possible.
We will integrate PayPal soon.
Even better, we have a free Account wich includes 500 requests a day. Use this Account as your sandbox for testing and implementing. Trials are a nice converting method but they expire. Sign up for our Free API Key and use the sandbox as long as you want.