Easier?
I think this is relative! I haven't advice for this.Sorry I mean cheapest to mine a altcoin that is less electricity used as possible of a altcoin in the top 100 rankings.
Cheapest?
You could try this! (Almost zero cost)
Mining is just math, after all! Try brain mining! - You can mine whatever coins.
A long time ago, the easiest way to mine was cloud mining. The most popular cloud mining was Cex, which owned one of the biggest Bitcoin mining pools at the time. - GHash (2013-2016)
All miners' goal is profit! Even if someone writes a coin name here at a low cost to mine it, there's no guarantee that it'll make you a profit. Let's say you got the coin to mine at low mining cost, has a pretty good price, but tons of miners mine the same coin as you.
So?
The best way is DYOR!
Good luck!