I don't think it is a good idea when you can build your list for free. It is easier to get a good squeeze page and run it through the traffic exchanges. build your referrals in Traffic Hoopla and you can receive free traffic in the traffic exchanges and Free Solo ads to run in the top safelist.
Email marketing is the most cost-effective, efficient way to let your clients know what has been happening in your business. A well designed newsletter is a chance for you to showcase your image, identity and business progression. It’s an opportunity to notify clients of new products or services on offer. A good newsletter will direct clients to your blog, validating all the effort you’ve been putting into content creation. It’s also a good chance to simply say hello and remind your clients that you’re still around.
It's one way and a great way. You'd need to set up a good funnel to capture the leads. Leadpage, auto responder, tracking software.
Yes only if you have the right ppc traffic source and a good landing page. Google Adwords and Bing Ads is what i will recommend, if you are a newbie then you can try 7 search ppc they have cheap traffic but the quality is not the best compared to google and bing