$8.15 after $$5.00 rebate
https://www.amazon.com/gp/product/B00DJ83070/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1ASUS USB Adapter with Bluetooth (USB-BT400)
3.9 out of 5 stars 715 customer reviews
142 answered questions
Price: $12.29 Free Shipping for Prime Members
Post-purchase rebate: $5.00 Rebate forms
Price after rebate: $7.29
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In Stock.
Bluetooth 4.0 USB Adapter
USB 2.0, Up to 3Mbps and Over 10 meters in free space
Frequency Band: 2.4~2.4835GHz unlicensed ISM band
OS Support: Windows 8 , 32bit/64bit / Windows 7 , 32bit/64bit / Windows XP , 32bit/64bit