General Business: Advertising location suggestions

I've been advertising my site for free on Gumtree for the last 4 or 5 months. I was happy, the figures for the site was growing and everything looked good. Until a couple of weeks ago when Gumtree decided that my site (link below)

http://www.weswapbooks.com

Was too similar to their swapping section and as a result I was competition to them. I don't really agree but I see their point and fine, fair enough. But now I'm stuck for advertising ideas.

I'm on a really tight budget and I was looking for some advertising ideas. Any ideas are good ones (please note at the moment my site is targeted at book lovers in the UK, hope to include the US after the new year).

I looked at some other classified sites but frankly GumTree is the best of these sites. I advertised on Facebook for a while but can't afford to do it for long.

So anyway, I'm open to any ideas for sites or maybe even something new...looking for inspiration as well I guess.

I would appreciate any suggestions.

I think the best place to advertise my site for now is general sites with lots of visitors (like gumtree or google) and bespoke book sites...maybe.

Thanks for the suggestion though, but I don't think an ad on here would attract people who'd be both interested in books and be in the UK.

Anyone any more suggestions?

my budget is very limited, like really limited, very very limited...

...I do plan to try AdSense fairly soon, facebook wasn't great in terms of what I spent for how many visitors I got but then that's down to the settings I put in.

I do plan to use facebook and adsense but having no money I was hoping someone had some other suggestions...

Try PSPTech they have great deals on advertising its $25/mo for a 136 x 136 ad pic or $5/mo for a link with a description pretty reasonable if you ask me.