Wow, this is an oldie but a goodie.
There's absolutely no doubt in my mind that you can MAKE MONEY without spending money.
I know ... I've done it. And we're not just talking pennies. I'm talking about matching the average monthly income within the span of a few days.
But there is a trade off ... as the old saying goes "Nothing's FREE."
And it's true.
Where you save in money, you usually pay with time ...
at least in the sense of this conversation.
There's also "inexpensive" options for building your business. Just because it isn't free doesn't mean we shouldn't consider the options just because we're "building on a budget." you'd be surprised what can be accomplished with a monthly budget of couple hundred dollars.
But yes, you can absolutely bootstrap a business. This is obviously a string option for people getting started that just don't have the cash. I know, I've been there too.
I think one of the most important aspects of going with free methods though is to not get stuck there, in that mindset. While it may be the easiest or most logical way to get going in many cases, it can also be a very dangerous place to dwell for too long.
At some point, to really go big and build a viable business with long term sustainability you're going to have to bite the bullet and throw down some cash to take it to the next level. This could be for paid services, employees, outsourcing of many types, etc.
You also have to consider the velocity of any given strategy.
Free may be "inexpensive" but it is typically slow in comparison with something like PPC (pay per click). Free usually has a lower risk threshold as well, but again, the return on investment may not be realized as quickly as you could see with a media buy or a well placed ad in a newsletter or high traffic blog.
So I say learn these techniques. Collect a good selection of strategies in your marketing toolbox. Use them. Put the free methods to use while you learn all the little nuances of internet marketing; they're great for earning your stripes without much financial consequence.
And as your business begins to produce revenue, get some of that money back into the business and begin exploring paid channels. Even if you choose to utilize free methods long term, now you know how to do it right and now that you have revenue you have the process outsourced on a mass scale, all the while freeing up your time to focus on more important aspects of your business ... like networking and brand exposure.