Hey! Thank you very much for answering!! Sorry, I didn't explain the situation enough.
Basically, the first person I want to introduce the game to has been reading a lot about the game and wants to give it a go in a competitive way. Not ULTRA competitive, but he would really like to play with points in a "legal" way, to really see what the game is about after a couple games. However, I am far from rich, and I don't want to spend a lot of money for an army I will possibly rarely play, but I would still like to play at 1k points with him (and any other person that comes to my house).
So I guess my question is, being more clear: what other stuff should I buy, besides the SC box, to make a 1k list without spending a lot of money but having a somewhat decent combo? Is it even possible? I would like to spend less than another SC box and, as I said, would really love to have a Curseling included for hobby and narrative reasons (or maybe a Gaunt summoner, a Chaos Lord, a Tzaangor shaman, I suppose any humanoid hero will do). With that I might not have much space (SC + Curseling is 870 points), but maybe I can leave some units out of the list for summons, like the screamers? I don't know Tzeentch's army a lot, even though he always attracted me, so I'm not sure on what to do.
I'ts already amazing that I got two answers so fast, thank you very very much! Please be my heroes lmao