Eshly wrote:So you think I SHOULDN'T offer a free week?

It depends on many factors. Here is how I worked it, again keep in mind you and I are in two different worlds geographically wise. And there are many who would disagree with what I am about to say, but I don't think it is a matter of right or wrong, I think it is a matter of what works for you and your situation.
If I am approaching a pub for the first time to get work, (note, I've already scoped the place out to get a feel for the flow).
My first conversation would be an introduction of what I do, and what I can do for them, (usually the same thing). Lets assume this is a 'cold' call and the reaction is not negative, but not reassuring either. The following conversation happens.
Mr. Pub, I notice that on Wednsdays your pub is quite slow why not let me come in on Wednsdays and you can see what I do and see what kind of reception your guests give me, how well I work with the staff, etc. Lets try for the next four Wednsdays and all it will cost you is my meal on Wednsday nights.
If I am really ambitious I may also point out that I notice that they have a line out the door on Fridays (if they have a line on Fridays) and I make the same deal for Fridays and I will entertain people in line so they don't decide to go somewhere else.
I will also encourage the manager to let people know that I will be there, as it becomes a draw, I would ask the customers that if they enjoyed the magic to please let the waitstaff know, (they in turn will tell the manager). In a month I will talk again with the manager and come up with a fee.
Please note:
I do not take tips. I am not in competition with the waitstaff, I will be making far more money than them per hours. I also make sure the guests know I don't take tips so they are not worried about it the entire time. If they insist, (and sometimes they do and it is rude to turn the tip down) then I give the tip to the waitstaff. (tipping waitstaff is just about manditory here in the US and Canada).
My job is not magic, it is to make sure the guests are having a good time and will come back. If a guest needs water or salt or a spoon I am more than happy to let the waitstaff know.
I am there to make the waitstaffs job easier, and I let them know. A dinner going to be late? find me I can entertain them and they won't know. Loud kids? find me I'll make a couple of balloon animals. Messed up an order? find me, I'll show em a few tricks while you get it sorted out.
Manager is watching? I'll borrow a dollar bill and switch if for a 5 and give the patron the five, (This is very impressive and usually they turn end up buying a drink with the fiver, which adds to the income of the bar and keeps them buying drinks) I believe in giving away 10% of my pay to such endeavours.
I've typed too much already and I can go on for an hour. But hopefully you get the idea, in the end you have to do what is comfortable for you, and what you can live with.