I was shooting an event when a rep from a marketing company asked me to shoot a couple of products on display. she said those products were from her client and she wanted to show them what she has done. I told her that I wasn't prepared because I didn't bring a tripod and it was really dark but she said anything is better than her point-n-shoot. so I took several exposures and think the best way is to combine the images to get a proper exposure of the product and it's surroundings. anyway, I have two photos that I can sell so my question is how much should I charge? the product in question is a big vodka company but I don't want to overcharge because there's a possibility that this might lead to more opportunities. thanks!