Re: The tip jar
Being in Oz, at least where I am, tipping is pretty rare. Sure, cafes have jars by the till but otherwise rarely do you see one.
I'm pretty confident that a tip jar here would not go over well. You would want to okay it with the venue way before the gig, but even then it could be seen as an insult. I would rather get more gigs in the future than risk the venues wrath. At most normal gigs, pub shows, festivals etc my fee is AU$200, and special events, weddings and corporate gigs it is more. That being said I feel that the pay is pretty good, and would not want to put that at risk in any way.
I agree that the way to make extra $ would be to do merch. No venues frown upon that here at all. Yes the outlay can be a bit daunting, but if it's more bucks ya want ya gotta spend some bucks to get it.
It's better to sit in silence and be thought a fool, than open ones mouth and remove all doubt..