We don't have our devs on call at all. Infra / platform ops are and I think they get 750€ per on-call week (not more than one week out of four) which includes two calls or two hours of call duration whichever is reached first.

After that it's another 70€ per call or started hour and it's the same if an expert who is not on call is asked to help out with an issue reported to on-call (but they may not answer / decline as there's never an expectation to be "soft on-call")

Overall that's an okay deal and some sorely needed extra money for the ops guys and gals. But all the same I'm happy that my devs don't need to plan their lives around an on-call schedule.