If you are looking for a cheap way of dressing up, I have found the best places to get cheap ladies clothes are boohoo.com and asos.com they do cheap and cheerful throwaway dresses in larges sizes which will accommodate a wide chest! I was talking to someone yesterday about this and thought he would look lovely in this dress http://www.boohoo.com/plus-rachel-off-the-shoulder-skater-dress/PZZ87486.html?color=157. They also do vinyl skirts in large sizes http://www.boohoo.com/plus-bridget-eyelet-lace-up-pu-skirt/PZZ84827.html?color=105 so plenty of choice at a really cheap price.
These days with more shops closing, you just cant get the variety anymore in a store, and the only place to get things in the right size is online, I have lost count of the people coming to see me who have wasted money on things that are far too small, as they have just run in to a shop, grabbed the first thing they saw and got out as quickly as possible, as least with these stores you can take your time and browse. Always check the size guide on the site and measure yourself with a measuring tape, don’t just guess what size you are.