So i thought ide post pictures of the ears I have made
first 2 are small cat ears (one just has long fur so it looks bigger) and i usualy sell them for $15 with one color inside and one outside
second 2 are medium and i sell them for $20 with one color inside and one outside
Large ears as $25-30 depending on what they are, with one color inside and one outside

the price also depends on if I have the fur already, if my local fabric store has it, or if I have to order it online. there are also additional charges for more than 2 colors.
the inside of the ears is either felt or fleece and they are usually put on headbands, i can also put them on hair clips if they are small enough or leave them off for you to attach them to whatever you want like a wig.
the headbands also have a casing of felt and are padded behind the (wearers) ears for comfort for long periods of wear so you wont get a headache (maybe thats just me)
These are hand sewn due to them being so small, larger ones may be able to be machine sewn.

all the ears here except the 3rd ones were made for customers.
ive made one more set of white ears for myself, i wore them everyday for a year or 2 and so i can say these are very comfy and do last quite a long time... just be careful not to put them in the dryer >_>'' ...