Is without a doubt to offer a service. If you can figure out a service people want they will shove money into your hands whenever you need it. One of the best examples of this I've seen was when I was using an app called Nextdoor. I highly recommend this app for people who like to be in the know of your local neighborhood activity. Your neighbors are posting able local events, lost/found pets, suspicious activity, stuff they're selling, etc on that app. Well apparently someone got the bright idea to offer his power washing services on the app. This was brilliant because the neighborhood I live in is middle class and with private homes. He offered free estimates whether or not the home owner was home. He had like 45 replies in no time at all. I found out his pricings were from $35 and up. Single family house $175. Single family drive way $50. Walk way $35-$50. All townhouses $50 front, $50 back or $85 for both. Drive way $25 and walk way $25. And he also do piers. But say you don't live in the best of neighborhoods. The app doesn't care. You're the one specifying where you live! So in essence you could prospect in as many neighborhoods as you're willing to travel to. Home Depot has power washers but want $55 for 4 hours which is impractical. But one could just try mold armour. It's a spray that attaches to their hose. You spray it on, wait 10 minutes and rinse it off. It reportedly works great and if you're unsure slash your prices and offer a newbie promo to see. Otherwise, you could use that very same app and ask to borrow a power washer and then watch some youtube videos about how to do a good job. If you don't want to get your hands dirty then just see what services people are clamoring for on here and offer that. No need to wait for SEO or spend tons of ppc to make some decent, on demand cash when you really need it. Offer a service, think convenience, and make that money! Good luck!
Offering a service is okay if you're of the trade time for money mindset I guess. It's not for me though. It might not be as quick (although I believe it can be) but to me creating your own digital product and marketing it is much more rewarding.
What JoeSpirit said. I don't get the mentality: "Offer a service and money will flow into your life". It may, it may not. Offering a service is not everything (if it was every service oriented website or physical business would be doing really well). A great business idea / plan, being in the right place at the right time and patience play a very important role in one's business success.
Doing a freelancer job can earn money quickly such as offering SEO services, designing services, writing services or any digital services on fiverr, seoclerks, freelancer,...IMO
There's really not too many things that will earn money quickly. Many will take time. Even having your own idea will take time before it will catch on. It is really a mix of different elements--having the right good or service, being in the right place, having a good marketing strategy--these and some other factors will determine success. It still won't be overnight though.
Quickest way too make money is to offer an expert service with proven history of success in the clients but it will require well experienced personnel and established profession in the field.
There are many great ideas you can find by just looking around. But not everybody has the willingness to be a start-up. Reasons are, no adequate time, money or technical knowledge. Fortunately, you can over come all of them. Time you can spare at night preparing a business plan. For the money, there is a hell lot of investors. And for technology, you can outsource to some one like Cygnet Infotech who are efficient and pocket-friendly, allowing you to invest less and earn more. Take a step today to make a better tomorrow.