My sister and I like to make our own ears! Wire ears are easy; fabric ears are a step up.
The Dollar Tree has flower wire and lots of fake flowers we decorate the headband with. Cute, unique ears for under $10 ($5 is doable)! There are lots of tutorials online.
Fabric ears are slightly harder to make, but I'm very happy with the two pairs I've made. There are sew and no-sew; tutorials are online for each!
I love making my own ears merely because of how fun it is! The characters tend to appreciate them too and will often comment on them. I had Spider-Man sign a themed pair of my fabric ears and he loved them.
I bought a pair of rose gold ones at Claire’s. They always have a coupon online. I paid around $12. They are Disney merchandise, the only difference between mine and the park ($25) version is that the park ones have sequins on the back and front and my cheap-o ones had sequins only on the front.
I also ordered a 2 pack of regular Minnie ears on Amazon for $6.99. They held up fine all week through about 5 rain storms and 3 rides on Space Mountain.