For some, thing may seem like the end of the world, but for others such as myself, mainstream fashion can easilly be incorperated into a Goth's wardrobe. When talking about 'mainstream fashion', unless I am specific, I am reffering to places like Target and K Mart. Cheap stores that seem to sell everything. This is because most often this type of clothing is more generic and less fashionable. I.e things like plain black T shirts, tights, stockings, scarves, walllets socks, trench coats and even shoes can be found in black in these places and frankly they cost far less than buying them elsewear. (Execpt an op shop/ thrift store, of course. I generally do most of my shopping at op shops and second hand stores, but if you are looking for something in particular then things can get a bit tricky.)
However, one must be careful how they incorperate these sorts of items into their wardrobe because, as we all know, one is not in Goth fashion if they are simply wearing black. There is more to it than that. Of course, there is absolutely nothing wrong with a Goth simply wearing plain colours. (Not just black, but if you thing about it, everything else as a block colour would look a bit strange).
For example, black lace tights and a black trench coat can be worn with a long floating skirt, some lace up boots and interesting jewellery for a cheaper alternative to buying expensive clothing. These items, if you decide that there is not enough pizazz, can be embellished to your liking. However I would suggest that you wait at least a month or two before cutting anything up, you know, just to make sure.