Internal linking good? Also multiple backlinks from other domains?

Is good internal linking a way to rank your site higher? I am creating a very large table with about 120 different types of generic, related products on my money. I plan on putting a link in the name to a separate post containing basic information about these products, with amazon links on the table and separate pages.
If I put 5-10 internal links to other articles within my own site, would that help my rankings?

Also, if I created a type of tier 1 wiki to my site, containing all of the articles I made in the table, would it be okay to include links to my money site on every page?

Also, what if I used duplicate content from say wikipedia on those pages? What about forum posts? Are those okay to use? Or would I want to make it all original?

Stop thinking about how to develop your website for search engines and start making it easier for your visitors to find what they're looking for and convert into customers.

If internal links are helpful, then use them. If they're not helpful, then don't. It's pretty straightforward.

Obviously Wikipedia has a ton of internal contextual links but that has absolutely nothing to do with how their pages rank.

Also: do not use duplicate content for anything on a money site, ever. Fork out the cash to have content rewritten at a minimum, or preferably get 100% unique material.

Make it easy and simple to navigate and the rest should come along with visitors.

Agree with the above, but in addition avoid duplicating content, it will not help you one bit.