As much as it may sound like one of those clichéd makeshift ads (doctors hate him), I've been able to make quite a bit of cash online from home doing basically nothing. I don't have an exact number at the moment, but I think I've cleared $80,000 in the past year and a half starting from an initial investment of $10.
In case you haven't heard about it, there's a whole scene for betting in e-sports ("video games" as it's known old fashionably more) that actually has quite a surprising bit of cash flow to it. Personally, I've only dealt with what is perhaps the most prominent and developed one, involving the Valve game Counter Strike: Global Offensive/CS:GO, so I can only give my experience regarding that.
How it works basically is that there are in game items, weapon skins if you take CS:GO as an example, that while technically speaking have no intrinsic value; can actually fetch quite a bit of real world currency as ludicrous as that sounds. If you're looking for a shock, go Google how much some of these more expensive knife skins can cost.
As for the betting goes, there are 3 types it boils down to.
The classical form of betting, mainly done of the site csgolounge, that involves betting weapon skins on matches between X team vs Y team. Odds are determined strictly by the userbase. Percentages are based on how much value users put on one team as compared to the other team.
Bookie sites such as egamingbets that are more like the vegas type of betting. There is no dealing with weapon skins, just cash here. Bookmakers make the odds and take a cut of the pie.
Fantasy draft sites such as Vulcun. A different take on betting, inspired by fantasy football and fueled by the wallets of venture capitalists. You pay an entry fee and get into a pot, pick players that earn you fantasy points based off their performance, and hopefully win if you have enough points to put you into a winning spot in the league.
That's basically the gist of how esports betting goes, at least from my perspective. It's not for everyone I suppose since there has to be losers if there are winners, but with some understanding of the scene you're betting in, there's plenty of room for the well-informed to make money.
Regarding how these skins translate into real money, it's actually really easy now with services like OPSkins that handle transactions for you regarding selling skins for actual cash.
Proof for the skeptical-