Would you consider investing in a new online business? I own a very unique internet startup that should be 100% ready to go by the end of the month. I'm looking for an investor/silent partner (or limited working partner) to provide working capital. If interested, email me: firstname.lastname@example.org.
Now to your questions (I'm no expert...just my two cents):
I pretty much agree with most of what has already been said here.
Starting a business from scratch will be the hardest and perhaps most "expensive" route in the long run. However, there is a deep sense of satisfaction in seeing "my idea" come to life. But remember, there's no "easy way" to success. People who claim to make money "easily" are either scam artists, violent criminals, or invested years of sweat and personal sacrifice, overcoming trials and failures to discover their "easy formula". Therefore, don't underestimate the value of time. I'd say time is far more important than money (not preaching, just my opinion). You can lose money and make it back; the same can't be said about time. So if you plan on "supplementing" money with time and effort, make sure the business is something you really like and enjoy doing. Otherwise, you'll be seriously tempted to abandon the project after a couple months (wasted time).
As for buying an existing business, I'd say you shouldn't do it unless:
a) The business has solid existing traffic, consistent revenue (from sales, membership fees, or advertising), solid customer/membership base, and can demonstrate serious potential for growth. Due diligence is critical, so you probably would be better off hiring a reputable business broker (you still need to do your own homework).
b) It's a new venture that not only excites you, but you can clearly see how YOU (your expertise, skill set, personality etc...) will be able to take the website/business to the next level. Be careful though. Get objective advice. Sometimes we get carried away with what excites us, and forget that a successful business is really about what excites OTHER people. Although the selling price will be cheaper than an established business, this option will of course require MUCH more effort, and could end up costing a lot more in the long run (time and money).
Anyway, I hope this helps. Let me know if you're interested in what I have. All the best to you.