I'm sure most of you have perhaps heard of this, but I happen to run across a cloud mining service that enables you to cloud mine without investment. It's called multimining.
I've only been using it for approximately 20-24 hours, and in that time I've acquired 0.00133 BTC. Payout is unconfirmed as you have to have a min balance of .05 to withdraw.
I have read many reviews on the website and there are reports of it being both a scam and legit. I figured I would give it a shot as there is nothing to lose as it simply runs in a browser and I haven't experienced any negative impacts (resource consumption), and of course because no investment required aside from computer/electrical/internet. They do have premium plans available which will increase revenue rates also (not required).
If you're interested, the website is multimining.website, and if you'd like, you can use my referral link: https://multimining.website/index.php?reffid=q6WyqpqY and if not, just use their direct link: https://multimining.website
If anyone has used the service with either a negative or positive experience, please share :)