Felt is cheap and easy- basically take a sheet and cut into the preferred size of triangle (double it up if you want, your preference), bring the bottom ends together into the ear shape, and stitch shut and onto the wig or onto a hairband or clips. The ears for the Twilight Sparkle costume in my avatar were made that way.
Originally Posted by Moofingham
There is a vibe here that says "We're in this together! Through thick and thin fabric! Through cold water washes and burning hot irons! Though we might super glue ourselves to our projects, cut holes/gashes/oh-god-mom's-gonna-kill-me into the dining room table, we will stand strong together. Unless there is a 75% off sale at the Fabric store. Then you're on your own. And get the hell out of my way." <3