Spending on Google Adwords?

My thoughts on applying and spending on Google Adwords could be a great thing. However, comparing on manual SEO which is free at no cost of money but time only, advertising is a good option but will coast you huge money. Advertising and gaining credits on traffic exchanges can also help my site going up to the SERPS, but this does not guarantee me unique targeted visitors. But through Google Adwords, no matter what we spent for it, we may earn huge traffic and generating visitors as well. Potential sales may be also implemented if we have Clickbank or other CPA ads like T3Leads. I am not ready yet to spend on Google Adwords, because I have not enough money to spend for it. For now, I'm doing the real SEO manually but cost me too much time, but results are always granted.