Yep Marisa, like Corey and Uncle Roy said, its the worst part of the business/hobby. If I could, I wouldn't sell to the public at all. There's a reason that working in retail sucks. Its because PEOPLE SUCK! Ha ha, just kidding (sort of). But yeah, Canadians are notoriously cheap and a lot of people (not all) will try and barter back and forth trying to get better prices, free shipping, etc etc. I don't mind that. The bad part is when a deal is set, and you don't hear from the person for a few weeks, and they miraculously email back asking for the animal at a cheaper price!
Which is why it helps to have a set price and just stick to it. I don't care if people sell the same animals as I do for 1/2 the price. Know the quality of your stock, know its place and value in the market, and charge accordingly. Be fair not only to your customers, but yourself. Its the people that have "fire" sales every year because they can't house babies or they are quitting the hobby that make it harder for the legit sellers. But such is life.