Seitan is a delicious meat substitute which I ate very often during my three years when I was just eating vegan and vegetarian food. Since it is very expensive to buy (At least here in Germany), I can only recommend to do it by yourself, because it can save you a lot of money and you also get much more for it.
100g Gluten Powder
25ml Soy Sauce
1Tsp Paprika Powder
(Spices are variable and can be exchanged to fit your own taste)
Some Vegetable Stock
First, mix the dry ingredients in a bowl. Since seitan is tasteless and seasoning it after being mixed with water is nearly impossible, you should not be stingy with the spices at that point.
Once you've mixed all the dry ingredients, add the water to the bowl and knead everything until you get a "rubbery ball". Split it into several small portions and put these in a Zip bag (Call it that?).
Fill the bags with the vegetable stock and then put them in a pot of hot water. Let the Seitan simmer for at least one hour on low heat. Afterwards you can process the Seitan at will.
It's best to cut it into thin slices and fry over medium heat. This can get a bit tricky as Seitan is very rubbery if it is fried too short (or the slices are too thick) and becomes hard as stone if fried too long. The problem with this is that the window is extremely small from gummy to rock hard. So always have a good eye on the seitan while you fry it: D