I've given away some gift certificates for Christianity Haven and for me it was more of a morale thing because everyone wants to get something for nothing, right? As long as there is a set limit that you'll spend on your site then it's okay to let that money go for the project. I see it as a hobby and I'd be spending money on paints and paintbrushes anyway since I'm an artist so this is one more way that I spend my money to enjoy myself (through my forum).

I can understand your point and would you believe it that I pay for writing articles on one website? Yes, that's true, the charge a fee to post your articles but that is a guarantee that you will earn regular income for a limited time. However, that income is enough to bring your investment plus profit.

I believe spending your money to make money means to make an investment. But, I don't know where would you invest? Is it something you know; a particular field. Or, Something you are quite unknown but know you know has a scope to make a lot of money.

Hard to make money without putting something into it, either time or your own money.  Usually if you give money, you get more back but it depends on whats going on.

I see what the OP is saying. In fact, many have a naive view of marketing.  As is stated with the title, it takes money to make money.  However, though, the amount can vary.  For instance, the startup for a McDonald's is way less than for a Patreon (a typical one).  With fast food, you're looking at $100,000 minimum, while with a Patreon, 20 K maximum (both are rough estimates).

Anyway, as @TimeRider noted,  it's incredibly important to pick  the niche wisely.  In other words, do you really know enough about the topic to make an appealing website?