On line is much different than live. You will lose your stake and be prepared to be asked for a reload. If you're going to mix friends and money, accept the fact that you're basically giving the cash away and make it a gift.
There's no market for this so there really is no norm. Charge whatever you need to feel good about giving him 2500. If it's too high and he doesn't like it, he can just say no and find somebody else.