@Kokoloco - Some ideas for you:
I would put it all in one place, such as the dining room table.
Then clean the place you're planning to store it, such as the bathroom cabinet or make-up bag.
Then put things back in order of when you plan to use them, starting with your favourites. What I mean is, you might be in the habit of using something you don't really like, so don't put this back - you deserve better. Also, don't put back anything which you've had 6 months+ and haven't used yet. (I've kept one small bubble bath as I hardly ever have baths but want this for when I do.)
I would also clean everything before putting it away. (Bin/recycle old make-up as it's probably filthy.)
As for your issue of spending money to look good. Maybe reassure yourself that you're doing your best and it's good to try new things sometimes. You've also helped to provide jobs for people. (Say whatever works to yourself.)
You might be able to sell some of it - I find getting money helps me to get rid of things. You might also be able to donate some to a women's refuge - such a good cause - again, this might help ease the process for you. Or maybe you could have a party and give some away to friends in a party bag?
Long-term, you really don't need much. One small make-up bag works for me, plus a few bathroom products. I also use natural, kitchen products such as olive oil and coconut oil (great for removing eye make-up).
Hope this all helps.