Pay For An AD on a website...

Hello,

I'm currently working on SE0 concerning my blog, and as the same time i add more and more content to my website...
Anyway, as everybody, i'm looking to increase the traffic to my website, and as everybody i'm exchanging links, buying them, buying reviews and blablabla...
However i'm working on the Forex niche (even if it is a "crowded" niche, that's a domain that i really know as a trader) and i realize that buying links and all the stuff is really expensive in this niche...
Let's know go to the main problem... I've found a forex website on where it would be good to make some advertisement, the only problem is that it cost $90 a month to put a little 120X60 banner on the blog...
So here is my question, do you think that it is worthwhile to buy a space knowing that the website traffic is :
Site traffic:
10,000 unique visitors per month
25,000 page views per month
Site wide ePCM of $185.36 - high referring potential !

It is by the way ranked third for the term forex blog...
Here you can have a look to the website : Forex Blog by Lloyd

Thanks for you help !!
Samuel.