This works for each of the three standard sizes (small, medium, large, I don't think it works on super). A trick to make some walking around inf is to put in bids on large inspirations of less desired types, transform them, and put them on the /AH (or use them). I'll frequently buy oranges, change them to purples, sell them. It's not a ton of inf, but if you want to be self-sufficient this is one easy way.
Also, for more quick start-up inf, sell the large green and the large red inspiration you get from the tutorial once you have enough inf for the posting fee. As an added bonus, once you are rolling in inf, put in bids for large green and large red inspirations to pass it along.