Tea Tree Oil is believed to be beneficial to cure skin problems and most drug store cleanser, toner and what not claimed to have tea tree oil as their ingredient and it can help to fight acne. Actually there is not much evidence on the efficiency but I've been using product containing tea tree oil and it actually works!
My go to tea tree oil brand is Aiken, because it is easy to find and cheap. The Aiken toner really does help me with my acne problems and it also helps to reduce scars. I've been using this toner on/off since high school and I think its a cheaper alternative for those who can't really afford high end acne treatment.
The result might be slow but it is effective in a long term. Now I'm pimple free (as I'm writing this) for quite some times and I hope my skin continues to be pimple free forever.
P/S: You can try Cosmoderm Tea Tree Oil product range too, I heard that they're quite effective as well.