Firemaking is the second hardest skill to train in CorruptionX, Slayer being the first.
To obtain supplies for firemaking, use the command ::buttfuck, or ::home using the Home Teleport spell in your Regular and Ancient spellbooks, excluding lunar because Lunar's home teleport teleports you to a Hookers House.
Trade Duradel, do not talk to him, that's for Blow Jobs.
The other NPC (Needle-Penis Collectors) that sells logs for Firemaking would be the Shop Keeper, next to Duradel. He may be glitched, at the moment, he is selling Viagra for 50% off. Hit him up.
Ps, that shit works.
Cost: 38 Coins
Oak Logs 
Cost: 51 Coins
Cost: 8 Coins
Cost: 30 Coins
Cost: 452 Coins
Cost: 1,314 Coins