Without money all you have is time. If you want to save money in life you need to figure out how to do things on your own. One example is changing your oil, if you know how to change your own oil you can save a few bucks over going to a mechanic.
Then you have the time commitment, it takes you the time to drive to the store, shop and drive back and the time to do the oil change. Overall you'll probably spend an extra hour overall. Which is better spent working.
And don't forget, if you plan to be proper, you'll need to drive that old oil back to the store instead of dumping it down the storm drain.
So basically changing the oil yourself is not worth it. The only thing it gains you, is the ability to thump your chest and look down at all the "pussies" who can't change their own oil.
The franchises charge around $30, with occasional discounts to $25, and the independents are that.
It's easy to find oil under $2, but at $5/filter and $2/qt, a 5qt oil change costs $15. Most foreign cars take less oil and both the oil and filter price are high, so $10 is more like it.
So, we're looking at saving $15-20 after taxes for less than 30 minutes work.
If you want synthetic oil, you can save even more. Dealers charge >$10/qt for high-grade synthetics which are readily available for around $7 (and, if you pay attention, $5),
It's easy to always buy oil and filter on sale because oil changes are not a surprise. (You can take the old oil back when you buy new if your community doesn't have curb-side recycling - San Jose does.)
Is it worth it? That depends. What were you actually going to do with that 30 minutes?
cooking food is a good example, on average you can have leverage up to 10x over dining
generic drug is another, 2-50x leverage over branded one
chemistry ... up to 10000x -- i invested $3 for a kg of washing soda and citric acid (many use weaker base like baking soda and weaker acid like vinegar) which could last me a lifetime. now i rarely go to personal care (shampoo, soap, toothpaste) while at grocery
imagination ... up to infinity (free) -- coding, writing, entertain oneself, etc
changing oil is "service" ... as such, the leverage is low, 5x top
many say it's better to buy than make since you have to spend time making it yourself ... they conveniently forget that they too have to waste time buying (going to seller, making selection, putting order, waiting, paying, reordering)
Given depression, I think that there's a profitable market nowadays on telling people they can get rich without money, while living in their parents' basements, and jacking off. Of course you can do that. However, if you have to read articles to motivate you, or give you those good, warm and fuzzy tips you probably aren't ready to start business because no fuzzy article is going to save you.
Let the downmotes begin.
You're going to make mistakes running your first business. Once you start hiring, the stakes get much higher. It's just not about you anymore. Someone's else livelihood is on the line. Take your time. Use abundance of caution with your first hires.
