Affiliate banners required for e-retailer with 50,000+ products (long term role)

Design details: As per job description
Ideas for the visual style: As per job description
Extra notes:

I own BuySend.com, an e-retailer with over 50,000 products. We have recently started using an affiliate company called Affiliate Window to drive traffic to our website and we now require affiliate banners for publishers to use as links on their own websites.

Eventually we will require specific banners for each of the hundreds of categories on our website, however to begin with we will just start with the main 9 categories that you can see on the front page plus a few general banners covering all products. If the banners you create are successful we will be looking to work with you long into the future, having work available for you on a daily basis.

Do you know what the general dimensions are for affiliate banners? I am thinking a long horizontal, a long vertical and also a square shaped one? Each of these banners would have the same design with the content shifted around to fit the dimensions.

To make this as successful as possible the banners need to have branded products in them relating to the specific category they link to. Brand logos should be included where possible to add authenticity. This will be similar to the hero banners on our eBay advert here: http://www.ebay.co.uk/itm/131579219105

Obviously the main aim is to get potential customers to click on the banner, so a strong call to action is vital.

If you have any banner examples similar to what is required for this project, please attach them with your reply.

I am happy to pay up to £100 for the first set of 9 category banners plus the set of general BuySend website banners.

Please let me know your thoughts and ideas for these banners as well as your price for the initial work detailed above.

Paul Brown
Director - BuySend