Is there a site (or formula) that easily calculates returns using difficulty / hash rate? I'm just a novelty miner, looking to be cool and do my part to decentralize. Not looking for a return on my investment.

However if I'm going to spend $100 or so I'd like to calculate how my options will fare. Any sites that have no affiliation to hardware, just calculate returns on current difficulty &amp; a hash rate that I specify?
Have a look at coinwarz.com - it list's alot of crypto currencies, difficulty and includes a calculator to measure ROI when considering mining.