I am looking for ways to market my book on a zero dollar budget?

[RunningBear]

Be active on as many writing forums as you can, and include a link to your website in your signature and profile.

Don't have a website? Get a free blog from blogger.com and tailor it to your needs. Include a blurb and an excerpt, plus a link to buy it.

Ask if you can display a card or poster in local bookshops, charity shops, newsagents, libraries.

See if you can sell a few copies at car boot sales, markets, jumble sales etc.

Get people you know to read it and post reviews on your Amazon page.

Maybe you could join Shelfari and include it on your 'shelf'? (In Shelfari people who read the same books as you can see what other books you liked. Not sure if it would necessarily recognise a self-published book though, but it's worth a try, right?)