Putting up a stall in a fair

I've been running a clothing website for quite some time now, and it has been doing well. A lot of people like the clothes that I have put and it brought me some notoriety. Through word of mouth, an organizer heard about my business and asked me if I'd be interested in putting up a stall in a fair cum exhibition they are organizing for both profit and non-profit organizations. I totally jumped in, and was given pamphlets to promote it around. However, I never got around promoting those pamphlets. I have a fanpage nearing 800 likes, and I am yet to make an announcement about this. Nevertheless, I'm pretty sure that the turn up will be quite good, because it will be on Sunday, and getting leads to an offline brick and mortar location is a lot easier than to an online entity.

The main issue will be dealing with these people one-on-one. I am quite good at communication, and I will be helping my wife, because this particular exhibition is women-oriented and so even the clothes will be all ladies wear. I've done telemarketing before, but never really sold something like this by a face to face interaction. What I'm really worried about is the bargaining folk. Trust me, where this event is taking place, that place oodles with folk who love to bargain. I don't know who will be worth the effort and who will be just wasting my time. I am nervous and also very excited as it will also be a first time experience of how it will be like to run a retail outlet. So, I was hoping if you guys had any tips at all for me that will come handy.