eBooks Membership Website - Help Needed

I have a ebooks membership website, targeting global traffic as there are no geographical barriers when you are selling soft copies of books.

My priority is USA, need your suggestions in basic online marketing execution.

SEO > Paid > Bots etc.

SEO takes time.

Go for paid marketing if you have budget.

I hope you aren't one of those guys who steal eBooks of other people, and then offer some shitty $5/month membership on their shitty site, for unlimited access to the books.

If you are, you won't make it with paid traffic. (Too little conversion rate to make positive ROI for $5 memberships that typically last only a month).
You won't make it either with SEO (google hates such sites, and you are basically just copying the content)
And I have no idea how you hoped to bring traffic that can convert with the help of bots???

Anyway, if you are a legit content creator and have made/paid for some excellent original books that you plan to sell, then I apologize . And you have a lot of options in that case.

No, I am not the guy who steals others ebooks, I am working on some SEO tools and will sell them on my membership website.

you can promote your site with google adword or bing or facebook ads

If it's a legit site, then it's better to promote it with Adwords or Facebook ads. SEO needs a lot of initial investment and your site ranks after some time. The bots are useless as far as traffic & conversion are concerned. If your site is in a general niche or attracts normal people, then you can try native ads with clickbait images.