Best SEO Software or Tool

Can anyone recommend good SEO software. I was using the free version of the SEO Powersuit from link-assistant but i can get over the cost. Then when i looked around a lot of places want to charge you like $100 buck each month. That's way to much. Anyone have experience with something good that's not so expensive?
Please don't just promote whatever affiliate program you belong to.

See original post by TrueVapor