You need: Cardboard egg carton, wax, dryer lint, cotton/cotton balls, sawdust or a combination of any of these.
I save up the cardboard egg cartons (you only need the bottom part) or the bigger flats, until I figure I have enough. I have a small container that I put dryer lint in when I clean out the lint trap. If I think of it, I have Craig bring home a bit of sawdust from the shop. Have another container that I toss candle stubs into. Also, I find candles pretty cheap at yard sales, thrift shops, even the dollar store. Sometimes, I have people give them to me (they know I make fire starters.) If all else fails, you can buy bars of wax in the canning section of Walmart, the grocery or hardware store.
Just stuff some dryer lint, sawdust, cotton or combination, in each section of the egg carton. Set the egg carton on some newspaper, wax paper, foil, etc. so you don't get wax on your counter top or table. Melt the wax*, pour on top of lint. You only need to coat/saturate the lint, not fill the cup with wax. Once they have cooled & hardened, you can put the egg carton in a zip lock. This works especially well if you use sawdust - helps keep things neat.
When you want to start a fire, or charcoal, just tear off one of the egg sections, set it in the fire pit or under the charcoal starter & light. It will burn even if it is raining because they are coated in wax.
Another way to make a firestarter, is to just dip cotton balls into melted wax.
I usually make these once a year, in the winter, & then we are set for the next year.
*For melting the wax, I use an old sauce pan & a #10 can (like a metal coffee can - or you could use a large juice or veggie/fruit can). Put about 1 1/2" of water in the sauce pan, put the wax in the can & set can in the sauce pan. Heat over medium until wax is melted. I also use an old wooden spoon to stir the wax as it melts. You don't want to use your regular cooking pans/utensils, as they will get wax on them & it is a pain to remove. I keep my pan, can & spoon with my other "stuff" to make firestarters.