Would you sell out your best friend for something you really wanted (realistically)?

It can be in many different scenarios. For example:

If you very best friend was in trouble, would you sell him out? And let us presume he was wrongfully accused and that he did nothing wrong. If you sell him out, he would get in serious shit.

Or this situation:

You had the infos to your best friend's secrets. If someone would give you whatever you wanted realistically (money, etc) for those secrets, would you?

Bunch of situations, but those are to name a few.