A cup of tea, a bath, a book, a walk/run/bike outside, time in nature, a splash in a puddle, good'ole'movies that make you cry and laugh at the same time, stitch and b*tch with friends... self care need not cost a lot, or even take much time. My self care is my bike, I need to be outside, and active to be mentally healthy. To fit it in (I have a 1,3 and 6 year old) I bike to the store, or to work, or to my kids soccer whatever trip makes sense that week. I'm outside in rain, snow and sun, and usually it's an activity I do with my kids.
Practice letting go of things, of mom guilt, of chores, of home cooked meals, of clean floors - whatever! But expect less, do less, and be more, breathe. And I mean practice, because we're not good at self care, it takes time to learn it for you especially if your out of practice.
Hugs, be kind to your self.