Since I don't have a lot of money right now, I don't really pay for PR. Since I have a lot of friends who also own domains, and since many of them work in similar areas, we can publicize off of each other. Human connection and networking is a great thing.
Yeah, if you have some friends with good websites then you can easily earn minor page rank in few months.
When I first started out market my first website, I paid for links (up to $20/month) and did manual traffic exchanges. I managed to get page rank 4 with this after just a few months, not bad at all for a first website that i was marketing.
With everything I've learned over the past year or so, I've learned that manual directory submissions, link to your website in your signature on forums, and article submissions as andreww38 mention above, are fantastic and free !
I submit my websites to as many high PR directories as possible, and as many search engines as I can possibly submit too.
I also try to buy/trade link spots on other high pagerank websites.