Badges range in price depending if you go oem or not. From memory I paid £5.99 but they weren't oem, they were the black and white carbon fibre type off eBay again.
The ones I had ordered weren't designed for the indicator roundel but I only had to cut of 2 plastic pegs & then I puts lots of silicone on it, placed the badge backing on top and let it set. The physical badge itself is just an adhesive sticker basically.