I'm considering buying the following plugins...does anyone recommend another that may do the same work, but for less $$ on any of these? or, do you know where I can get a coupon code for any of them?

ReviewAzon
http://datawebpro.com/reviewazon

MaxBlogPress Ninja Affiliate
http://x15a.com/ninja_affiliate

Caffeinated Content for WordPress
http://mycaffeinatedcontent.com/

ADPS2 Affiliate Datafeed Profit System
http://x15a.com/wordpress_shareasale_datafeed_plugin

wptraffic
http://x15a.com/wptraffic

Utopia Ad Block
http://activeblogging.com/adblock/

phpBay
http://x15a.com/phpbaypro

phpOstock
http://x15a.com/Overstock_Wordpress_plugin