Paraffin wax is the cheapest of waxes and is great to use, but it can crack giving a mottled effect if you want to avoid this then use beeswax. You can also use paraffin with beeswax together.
You can melt the wax in a double boiler method (pan on pan) the same as you would melt chocolate. Or melt it in a heavy based saucepan. Heat the wax to around 170’F (80’C) making sure that your wax does not get to flash point.