How much are you charging????

A couple of weekends ago I went to my local farmers market. I bought a bottle of salad dressing, handed over three and a half of my English pounds and headed onwards... Later that day I popped to the supermarket to stock up on soy milk, and whilst browsing the shelves I noticed they stocked the same range of local dressings, so I took a closer look. The same delicious quince dressing was only £2!

My immediate thoughts weren't good! Why on earth had I been charged more than half as much again to buy it earlier that day? So I looked up the firm online and whipped off an email to the company...
They explained that this was due to the price of manning a stall at a market, the low volume of sales at market 
"Consequently the cost of the products have to be more expensive to even make a market brake even, farmers markets are a way of getting the brand out there locally so that people can taste the product, without making a loss."

Even though I understood the reasons behind his decision it was the inconsistancy in the pricing that had upset me.

As a business owner I have always tried to keep my prices generally the same, wherever I sell my product, folksy, facebook, my website or local market, whether it has meant me losing out or not, but I'd be interested to see what you all feel about this contentious issue...

If you are a business owner do you charge the same price across your retail outlets or vary them? Do you adjust your prices to cover additional expenses?
If you are a customer do you expect to pay the same across the board or do you expect to pay more or less from certain outlets?

I'll be looking into pricing in more detail for some upcoming blog posts, so keep checking back!