One of my favorite candles I liked to make are called Treasure candles. Treasure candles are really neat because they have little treasures you find when you burn the candle. It's a great gift for a friend. You can even have special meanings for the items to personalize it. You can create a key so they know what it means after they find each trinket. You could use it to give a bigger gift like a car or a ring. You could even hide a gender announcement or ask someone to marry you. Just find some small metal letters to spell out the letters.
Wax. I like granulated wax because it melts faster. You could recycle old wax if you wanted to.
A big can
A big pot
A few small metal trinkets. Make sure they aren't plastic or they will melt.
Melt the wax in the can over boiling water. Be careful not to let the can fall over or allow water in the can.
Prep the candle holder with a wick and wrap the wick around the pencil at the opening of the mold. I like wax coated wicks for this. It helps it stay in place better.
Pour a layer of wax in the holder and let cool. Place a trinket on the layer and then pour the next layer on and repeat until to you get to the top of the candle. Trim the wick and you have your very own treasure candle.
Be very careful when handling the wax and the trinkets after burning. They will be hot.