My dad goes to these auctions that always sell stuff really cheap. My tack trunk is an old military trunk that he bought for $2 and I painted and my first aid box is some other little chest.
I've packed some old human blankets under stable blankets during a cold snap while ours were at the wash.
I stole a bottle of my mom's shampoo that removes yellow, she bought when she went to the hairstylist and they colored her hair copper on accident to get the yellow out of my gray mare's tail. Shhh. Don't tell her. XD
Our barn owner has chopped up fun noodles too use as head bumpers at the tops of horse trailers.
I have a couple pairs of actual riding tights for hot weather riding, but usually I just ride in skinny jeans, serve the same purpose and save time between going home and changing after school.
I'll have to make a trip through my stuff and repost if I find anything else odd.