Wireless charging with Koolpad is not expensive at all. I got my coil separately before I knew they had them too. LOVING it for about a month. $37 total. I cannot tell the coil is there at all. Working with my Spigen cover. Also posting as Wireless Charging.
Amazon.com : Koolpuck Black Body with Blue Grip : Cell Phones & Accessories
Amazon.com: PThink Ultra-thin 0.5mm Qi Wireless Charging Receiver Card Coil for Samsung Galaxy Note III 3 N9000 N9005 with Full NFC Support: Cell Phones & Accessories
Lots of more expensive and bulky options. This one works!