Does anyone have any tips to increase page rank in a way that doesn't involve money?

you can read here:

http://www.seochat.com

Link exchange with sites having higher page rank. Most probibaly the sites having simlar subject as yours.

Create informative, useful and quality contents with appropriate keywords.

Well, You should also concentrate on building link popularity, enhancing number of both inbound and oubound links.

Best way would be to advertise on high PR sites and make some link exchanges with other sites with a reasonable PR.

writing and submiting articles to article directories is one popular idea to increase link popularity
participating in forums and contributing positively also can get more inbound links
above all, having a good information rich, useful site is the key to increasing linkpopularity as other webmasters link to such relevant and useful sites sometimes without even asking for a link back.

Get quality links from relavant websites

If you spend a good few hours finding and submitting to directories, you should increase your pagerank, although it will take a while to change.

basically, you will need to optimize your web site first. Submitting site to directory doesnt help if your site is not optimized. also, if your site PR is low, it's hard to exchange link with higher PR sites.

pay attention to anchor text, title, meta tags...

I am not the greatest at this yet, but I have seen and heard that posting your link in blogs can help, however if you use some of the blasters they can seem not to work so well, so manually doing it probably better.

Well, I did post a link of directory sites here:
http://www.webhostingtalk.com/showthread.php?t=499789

However, I'd caution against asking the question "How do I increase PageRank" as much as "How do I increase the number of potential sales leads to my website". Both questions are *not* synonymous.