So, what is the catch?
You buy a sub for $1, but each sub costs $5 for the account. How can you profit if you pay $5 to earn $1? And why wouldn't you just use these accounts for youself to earn $3.5 per sub instead of $1?
Presumably these subs are being made from stolen credit cards. I'm not too sure how hard it is to become an affiliate, but I would assume all of OP's Twitch accounts have been terminated for fraud, and the same is likely to happen to anyone who uses this service.