If you do not want the proper stuff and on a tight budget, you can use an old unused candle, I used to melt old bits of candle then, find a stiff cardboard container, such as one used for gravy mix or similar as they are coated so waterproof, you can stick something through and tie the wick on so its in the middle and hanging, it works but I used a candle that I did not like anyway so cut up the wick from that and used the wax. you can make them short and dumpy, no need to fill them up, leave them to cool down for as long as possible, even pop in the fridge, then you can cut or peel open the carton, I never tried other cartons but the same thing would apply, make sure the wax is not too hot though and do it on something that does not matter

I only use tea lights now due to fire hazzard....they at least are put into jars so do not need watching so much, I also sometimes melt the bits of smelly ones and add them all together, thats a good saving too, then you can pop a fresh tea light without the tin bottom, into the melted mix, then its last longer!
I have loads of old bits of candle, I use them wrapped in newspaper for fire lighters!!