For my Newbie self: Regarding 3rd party lenses

I'm looking at expanding my lens collection; so far I've only bought Nikkor lenses. My only issue is the price point for new lenses. I was wondering, out of the third-party lenses out there, which 3rd party brands would you recommend, which ones would you avoid? I'm looking for the best quality for the least cost. Any input any of you can...