I'm trying to find out what are the standard service/tech-support response times that are expected of a software vendor. We're being asked by a customer to enter into an agreement regarding technical support for a software application that we're selling.

Basically, I'm interested in the typical turn-around time (i.e. time to respond, time to resolution) based on the severity of the issue. And also, I'm interested in the financial structure of such agreements: i.e. charge/incident, bundle with unlimited incidents/customer etc.

Any information or suggestions of where to find such information (even examples of other software vendors websites) would be greatly appreciated!