My Ultimate Paint Sealant is $10 and should be enough to coat a vehicle 5 times if used properly. It is a synthetic paint sealant containing amino functional silicones that form a bond with your clearcoat at the molecular level. That basically means it lasts a lot longer. Standard caranuba wax has a melting point of about 106 degrees, and on a hot summer day your paint can reach excesses of 150. This heat degrades the wax quickly and it literally melts off your car. A synthetic sealant does not break down until about 230 degrees, and if it gets that hot you have bigger problems than paint protection!
The Ultimate Paint Sealant is applied like a wax, to the entire vehicle, and allowed to cure for 20-30 minutes before removing with a microfiber towel. Only a thin coat is needed, so slopping it all over the place has no benefit. Same goes for layering, it will not bond to itself, so layering is not beneficial. You can, however, wax on top of a synthetic paint sealant after letting it cure for 24 hours. A nice coat of a high quality caranuba on top of a sealant that has been applied to a finish that has be clayed and polished will give you a spectacular shine, depth, and reflectivity.