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Thanks for your response and I will take a look at the url suggested!

It would depend on whom you are using, usually a good agency is at least a few thousand per release based on my experience. It depends on either how beneficial their contacts are for your business or how wide their distribution. To get consistent coverage in quality publications you would need new angles and interesting pieces to keep journalists wanting content from you otherwise you'll only be getting links from the PR submission tools which may not be worth the investment of your time and money.

BTW: If you want to advertise with someone I would do the following: Get them to share key traffic and demographic figures (Google Analytics) Track their campaigns and click-throughs - use the Google URL Builder to build your destination campaigns, you will then be able to analyse in your GA account how your external campaigns perform. Generally websites accepting advertisers have inflated rate-cards and inflate their traffic. I would compare their CPM with for example running similar campaigns through Google Adwords (you might get more value from Adwords) I would also base your payment on performance - don't work on impressions or clicks, try and work on conversions - i.e. you pay nothing for impression/click but you pay a conversion rate - i.e. 10 USD for a user registration or xx % of revenue for any referred transaction. Be careful with paying for registrations (especially those not resulting in revenue), many sites will drive lots of signups to you but no actual revenue.

Thanks for the response. Could I set some of them to 'nofollow' would that help? As I assume the robot would skip crawling those nofollow link?

Sure. Depending on the site--could be quite common. I would fix the issues on the most "important" pages and devout the resources on creating compelling content.