I've been approached by one marketing company who has interested to put their advertisement on my site as their product testing. Further discussion will be on next week. I'm a newbie to advertisement issues. How much should I charge them in the first place?
It's not appropriate to disclose the url because of security reasons. It is about education advertisment.
Gotcha, I can't answer your original question then, but I would look at how well your site ranks, what your PR is, alexa rank, etc. and do theirs as well, and then just decide on an appropriate price.
Advertising rates can be determined by how much traffic you have, pagerank, and unfortunatly some people look at alexa ranking. Another way you can figure out how much you want to charge is by comparing that ad placement with lets say your Google Adsense Earnings. Lets say you have a header ad thats google adsesne and it makes you $50 per month. Would you replace that with someone elses advertisement for less? or would you charge the same or more.