Container candles made from recycled wax. I always save the stubs of pillars and tapers, and scrape out the leftover wax in jar candles. When I've saved up enough wax, I melt it all together and make new jar candles. The colors and scents mix together so I usually get some muddy color but I haven't yet had a scent that was nasty. For containers I use recycled jam jars or used candle tins. The wicks are the only purchased supply.
These aren't pretty enough to sell or even give as gifts, but they burn very nice and they are almost free.