Good information and advice
There has been a lot of good information and advice posted in this thread. I'd like to make some general observations. Please correct me if I am wrong:
1. Generating revenue from domains (parking, trading, or something else) requires an investment like any business.
2. It is possible to make a reasonable profit if you are willing to invest adequately and devote appropriate effort (work hard)
3. Most businesses should expect to lose money for 1-2 years before gradually becomming profitable at best.
4. The returns on any business or investment are related to the risk and effort you put in. If you invest very little money and effort, you will make very little return. If you invest a lot of money and effort you might still make very little.
As someone said, you can make 2-3% risk free on your money by putting it in the bank.
You can probably make 7-10% with greater risk by investing in stocks.
So, you should only invest in your own business if you can expect to make a higher return. The natural return of the industry, and I have no idea what it is for domains, is what you could expect to earn if you invested adequate amounts and put forth "average effort" with "average skill" If you are a beginner, lack the knowledge (or ability to learn quickly), or are unwilling to work harder than average, your retrun will be lower than the industry.
So what does all this mean in numbers? Let's say for argument's sake that the industry internal rate of return (IRR) is 25%, a fairly high number. I will spare the math unless you ask, but one way to generate this IRR over 5 years is to lose $3000 the first year, break even teh second, and make $1000, $2000, then $3000 in each of the next 3 years. You can divide or multiply each of these numbers to scale to your own investment.
If you expect to make more than that, you are expecting a higher IRR. This should tell you that you either need to work harder or take a higher risk of losing your money.
The bottom line is that you must have realistic expectations. If your plan is to invest $100 and expect to make $10000 within 2 years (or sooner) you are saying you think you can produce an IRR of 900%. This is completely unrealistic!
Personally I have only been doing this about a year and am tracking somewhere below the 25% IRR, maybe around 20%. But I did not know much when I started and have not put in as much effort as I could have so I guess I have done reasonably well.
Hope this was helpful.