You can buy candle moulds without breaking the bank, but there are probably things around the house that you can use.
One idea is a straight-sided metal container (small baked bean tin?) without too jagged an edge. That is for the sake of your fingers. Get some soft string for a wick (again you can buy the right stuff online) Make a hole in the base, thread the string through and fasten down the end underneath with sticky tape. Lay a pencil or something similar over the top and tie the top of the string to that so that the string is upright. If you don't fix the string it floats up or slides down into the wax. Stand your mould on a tinfoil food tray, or similar, to catch drips.
Melt the old wax in a pan you don't value, over a pan of hot water. Take it off the heat when it has melted and watch out for the wax catching fire. fish out the old wicks, or strain the wax through old nylon tights to get it clean, and pour in almost all of it. As it cools, it will shrink down around the wick, then you can melt what is left and pour that in.
If you want it coloured more brightly, mely a wax crayon in with the wax. you can make striped candles by adding layers of different colours. You can buy wax perfumes for candle-making too. lots of ideas online.