If you can save a lot early on in life, you can build up sources of unearned income, and this income will be exempt from payroll taxes. This is good news for investors and for retirees. Any pre-tax salary deferral contribution made to a retirement account, pension plan, or other pre-tax contribution will lower the amount of federal and state income tax liabilities, however, they do not lower your payroll/FICA tax - the FICA tax has already been taken out of gross wages. 
Investing in coins and collectibles: Buffalo nickels and Spiderman comic books are good examples of coins and collectibles that can rise in value, and thus offer opportunity for passive income investors. You'll need to get up to speed on the value of any coin or collectible under consideration, but once you do so, you're on the way to price appreciation on a commodity you'll be paying a lower price to buy, and will garner a higher price when you sell.

My grandfather knows how to cook because he is old he have in mind a lot of unique recipes from his childhood. He created a Youtube channel and explain how to make some of the recipes he know. Some of his video has 500K views, and are getting new views every day. If you read the book Rich Dad Poor Dad, you will understand better what I’m about to explain. You can see Youtube as your primary income, then you will work a full time job. But you also can use Youtube as a passive income. You will make less money but you won’t need to post a video every single day. Just create ‘Assets’, take your videos as assets, more you will have more money you will make.

Good suggestions. I have many of these. One word about the “app” idea. I had a great idea related to personal taxes that I tried to get off the ground with my accountant as a partner. I would say it’s difficult to do this unless you have a coder on your team. Hiring someone is not really viable financially unless the app is simple. When we finally got the quote for a coder to write what we wanted (and after doing lots of mock ups ourselves and getting a demo for investors) the estimate was about 750k just to really get started.
In order to generate $10,000 in Net Operating Profit After Tax (NOPAT) through a rental property, you must own a $50,000 property with an unheard of 20% net rental yield, a $100,000 property with a rare 10% net rental yield, or a more realistic $200,000 property with a 5% net rental yield. When I say net rental yield, I’m talking about rental income minus all expenses, including a mortgage, operating expenses, insurance, and property taxes.
The average period of customer use of the property, as figured in (1) above, is 30 days or less and you provide significant personal services with the rentals. Significant personal services include only services performed by individuals. To determine if personal services are significant, all relevant facts and circumstances are taken into consideration, including the frequency of the services, the type and amount of labor required to perform the services, and the value of the services relative to the amount charged for use of the property. Significant personal services don’t include the following.
Flynn, who blogs at Smart Passive Income and discusses his secrets at the Smart Passive Income podcast, defines passive income as “building online businesses that take advantage of systems of automations that allow transactions, cash flow and growth without requiring a real-time presence. We don’t have to trade our time for money one to one. Instead, we invest our time upfront, creating valuable products and experiences for people, and we reap the benefits of that time invested later,” he says, adding, “It’s not easy. I just want to make sure that’s clear.”
Hello from the UK! Fundrise and Wealthfront are only available to US residents it seems :(. Any other readers from the UK here? The only thing I have managed to do from Sam’s list is getting a fixed rate bond (CBS is having a 5-year fixed rate at 2.01% – not great but the best I could find ). Don’t know if the FIRE movement will ever take off here but would love to trade tips/ideas on how to reach FI and have the freedom to consider alternative rythms to living.
Creating original content that other people love can be very rewarding to you from a personal growth perspective (people value something you have created) and from a financial perspective (people are willing to pay you for it).  You create something once, but keep getting paid a royalty for it long after you completed it.  Music is a nice example.  You write/perform the song once, and then sell it online.  Each time someone downloads your song you are paid a percentage of that sale, what a nice way to generate passive income!
The E-Commerce model is an interesting one. The idea is that you get products made cheaply (usually China) through a site like Alibaba, ship them to a warehouse (or your own house!), put the product description up on Amazon (or your own website), get some sales and then send out the product. There is a big learning curve with this one and you need some money up-front to get the products.
One aspect you might want to add to your scoring is “inflation protection”. At one end, bonds and CDs generally pay a fixed nominal coupon that doesn’t rise with inflation. Stock dividends and Real estate rents (and underlying property value) tend to. Not reallly sure how P2P lending ranks- though I suppose the timeframes are fairly short (1 year or less?) and therefore the interest you receive takes into account the current risk free rate + a premium for your risk. Now that I think about it, P2P lending probably deserves a lower score in the activity column than bonds too (since you probably need to make new loans more often).
If you rent property to a trade or business activity in which you materially participated, net rental income from the property is treated as nonpassive income. This rule doesn’t apply to net income from renting property under a written binding contract entered into before February 19, 1988. It also doesn’t apply to property described earlier under Rental of Property Incidental to a Development Activity .

You must file a written statement with your original income tax return for the tax year in which you add a new activity to an existing group. The statement must provide the name, address, and EIN, if applicable, for the activity that’s being added and for the activities in the existing group. In addition, the statement must contain a declaration that the activities make up an appropriate economic unit for the measurement of gain or loss under the passive activity rules.
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