Internet Marketing VS Starting A Business?

With a few thousand to invest I would go for one website and utilize content marketing to promote it. This should drive both traffic and rankings and it's a long term strategy.

PBN's are risky, and it takes long to rank these days, I know a guy with 30+ Amazon affiliate sites and depsite him setting it up somewhat reasonable Google deindexed all his money site and 50% of his PBN. That joke costs him about $20k on money sites and another $20k or so on private blog network sites. All gone over night, but that's not all, all his sites (I only tracked down 30 of them, well actually a friend of mine did that) all had top 3 rankings so he made an average of $1k-$2k/month PER site. So that's a lost income of say $40k/month as well in addition to his lost assets and he won't be able to easily replace that as Google deindexed all of his sites.

I'm luckily in the position to see such thing as a calculated risk so I do use PBN to rank my money sites, but if you set a budget of a few K for yourself it would be real sad to see your hard efforts vanish over night as the risk is always there, undeniable.

In short content marketing works like this:

1) Produce great content that people are willing to share of course, to do so you head over to a site like BuzzSumo to find out which content is popular in your niche. If it's a top 10 or top 25 list or something that gets shared a lot then go completely overboard and make a top 100 list, nicely designed, perhaps with filters to navigate more easily through it and such.

2) Promote your content, contact the authorities in your niche, connect with them on Facebook, Twitter, start a Youtube channel, get yourself out there.

3) Contact the website owners that link to the current popular top 10 / top 25 lists, make them aware of your top 100 list, in other words beg for links

4) Offer money for links for the smaller often unresponsive bloggers in your niche, or come up with gifts or whatever incentive you can think of to achieve these links

5) Participate on forums, comment on their blogs, contribute, offer guest posts, do whatever what's neccessary to be known in the niche, a comment might not be a great link but if it drives traffic why not?

Establishing yourself as an authority obvious ain't easy but it doesn't have to cost a lot of money, most of your money will be spend on content for your website (unless you write it yourself). For the rest it's mostly time spend on connecting with people. If that's what you like go for it! It might not be a fast process but it will provide you with long term results and the more you put into it the more it pays off.

Have a look at SEO Training and Link Building Strategies - Backlinko for more information about whitehat strategies, I wouldn't recommend buying his temporarily out-sold guide as I heard from people that most of the guide content is also covered on his blog for free but it gives you a more detailed view of how or what. He's the living proof himself that it works, his blog ranks for competitive keywords in only 1 year time and he's getting tons of traffic from other sources where he's often featured as guest author.

A complete different way is to import products, same like you did in the past with your sports nutrition, ship it to Amazon and sell through their FBA program.