Getting error "A valid amount is required."

In our project we have used Commerce Authorize.Net module. We have not added any discount. No coupons are applied yet still when we proceed to checkout in testing mode we are always getting error as "A valid amount is required.". Our product price is $17.95 and when we get response from Authorize.net we are getting price as $-99.05 and hence payment is declined.

Can some one help us to solve this issue and let us know if we missed any settings then please let us know.