List Building or Launch Jacking?

Hey guys, I currently have two ventures I'm working on, list building and product launch jacking. I haven't really had much success with neither because of the lack of funds needed to invest (List is at 735, Last Product Launch failed due to google ranking), but I have come across $100 to spend, whether on SEO or list building, or any other method that is generally successful. Should I buy a SEO service from here? Solo ads? Something else I should consider? Please give me some advice.