Don't do PPC/media buys for CPA. You can earn way more by creating your own product and promoting it on the right place. I hope you are aware by not focusing on SEO you are losing a big market.
I won't suggest you start with $5000 if you don't know what to do.
Start a site, get tons of content for it, outsource keyword research and SEO then rank for profitable keywords and monetize with adsense or selling niche related products. I have 10-15 medium autoritive sites in this style, each getting at least 2000 visitors per day, in decent niches, each site making good cash. However, you need to know how to do things. I'm investing an one time average cost of 1000$ for every website's content and the rest such as keyword research, SEO and website building I like to do by myself.
EDIT:
I don't know your product good enough to give "targeted" advices but for product creation in general I would go with something like:
1. Think of the product and make good research on what the market needs. Create a comprehensive product and an offer that can't be refused.
2. Buy an aged brandable or niche related domain and pay it in advance for something like 5 years. (You need this if you want to go mad with the SEO, like I do and it can be useful to convert that smart buyers who check stats of a domain to see how legit is the brand that sells the product to them).
3. Have someone for 200$ to create a simple but effective landing page. Web 2.0 style, colorful, nice and easy to read fonts, impact images (get HQ images from shutterstock), nice order page - 200$ will be more than enough to get this kind of user experience. User experience weights tons when comes to selling.
4. Now you can point all the PPC and media buys campaigns straight to your site, which now has that awesome and high convertible landing page.
5. Create
www.website.com/blog (you can name it whatever) folder on your website, add 50-100 niche focused articles and make that folder easy to see for the bot and let it index and value all the content. Make sure you add an image or big link to your homepage (landing page) or you will lose the possible traffic that can arrive accidentally from the SERPs. I say accidentally because you will never do SEO to these articles. This strategy is only to have Google index all that unique content and value your website.
6. Start keyword research and select 20 profitable keywords for your main site and do SEO for your landing page (
www.website.com). Select other 200 low and medium comp. keywords and longtails for the next step.
7. Get 5 aged domains to target the 200 low and medium competition keywords (with 5 domains you will have an average of 40 keywords to target) - get content for these sites, 20 for each would be fine, and rank your domains and articles in Google. From these 5 mini-sites you can point (728x90 or 300x250 banner) to your landing page. Make it simple, just add articles, optimize your site and that's it, add banners and the traffic will come to you. Don't add pages or any stupid things that can distract the potential buyer, you just want to suck all the traffic to your landing page and selll.
8. Find some small bloggers or sites from your niche (with decent traffic ofc) that can accept a pretty small amount for an email blast to their lists. Trust me, there are people who write on fitness/weight loss as a hobby and most don't see the power in their list making them to sell it for cheap.
This is a pretty simple strategy for product creation and marketing (PPC, media buy, SEO and email marketing) that can make you few thousands every day.
Back in 2009-2010 I had one outsourced product that was super profitable at that moment and made me great cash in a time of 3-4 months. When I saw the easy drop in sales I just had to flip it because I had a great offer and I was fine. However, I wasn't limited only to few marketing strategies.
I would probably go and make a much more detailed guide on how to make cash with IM when you have the proper budget to invest.
So to be on-topic and answer your question, yes the best thing to do when you have a great landing page is to point the PPC/media buys straight to your domain.