I have one denim jacket (above), bought in the Zara sale about five years ago. I was really surprised when I found it because it was only $13 and is a good shape and quality. It is a very traditional basic straight style with no logos or extra details on it. There are really nice ones with a more fitted shape out there but they are very expensive for the number of times I wear my jacket. I wear it when my other jackets are too heavy or I want to make an outfit more casual.
Denim jackets are good for spring and late summer, and go with dresses, skirts, trousers and even jeans – if you don’t go too matchy-matchy. They can be thrown in the wash and look better the older they are. If you want to ring the changes you can put patches or badges/pins on them.