When you buy kits the first thing to run low will be the wax. So a reliable source of the right wax at the right price will be useful. There are loads of rigid and silicone moulds - the silicone ones release the wax more easily. It's a very satisfying activity but--- what will you do with all the novelty candles? Been there, given all my relatives and friends an owl candle.
Might be worth pricing up moulds, wicks and wax and colours as separate items so you can follow the designs you like best.