Host or join a clothing swap party
Some people think ethical or eco fashion is expensive (though if you choose something that lasts longer it may end up being cheaper in the long run!) but being a responsible consumer doesn't need to be more expensive, nor should it be less fun.
One great way of updating your wardrobe without costing you much is to throw a clothing swap party, where everyone brings items that they don't want, exchanging them with each other for free. These parties are also a fun way of meeting new people, and therefore a much richer way of "shopping".
There are different ways to do the exchange part, but the ones I've been to usually started with having everything in a big pile in the middle and having everyone say a thing or two (e.g. something interesting about one of the items they brought), and then trying things on, recommending things to others, etc. I've found a lot of things through these exchange parties that I would otherwise not have even thought of trying on.