Honestly, if you want an Antaresia because it is "the cheapest," then you shouldn't get a snake. Idk how old you are, but tbh you don't seem very mature or at all ready for a 20+ year commitment. If you are going to buy a snake based off of what is smallest, cheapest and easiest then it seems you don't want a pet or any responsibility, only a "cool" ornament. If you aim to get bitten, well that's plain stupid. Being prepared to be bitten, and wanting to be bitten are very different. You should do some research and decide if you ACTUALLY want a snake, and if you're committed. Gumtree is terrible. Big no. Don't buy a snake because it fits. Buy a snake and be prepared to set up a proper enclosure, based off what interests you, not what is simplest. I recommend reptile classifieds.