hey, sorry just catching up on these after a busy week!
I figured i would start with having someone write unique content for me for the top 100. and for the rest find someone really inexpensive to go out and copy information
This plan is perfectly fine until the words "copy information"
If you're copy/pasting content from other sites then you're really going to hurt your potential to rank. Rather than doing this, my suggestion would be to either put that budget you were going to spend on copy/pasting into having that person write more pages, OR have the second person use the first writer's first 100 as a reference point for how the other pages should read then write them for you.
Since duplicate content will essentially be ignored, you're better off with no content than a site full of duplicates - at least the no content option is free!
maybe use an online tool that modify's some of the words
This is what we refer to as "content spinning" and is an old tactic that no longer works. Even if the content is spun enough to be seen as unique, it will be so unreadable that you'll suffer for low quality content instead.
if they grab the descriptions from a 3-5 sites, then maybe google wont consider it duplicate content.
This won't actually help you either. Search engines aren't looking for completely duplicated websites, they're looking for duplicate content. Even if your content came from a mix of 1000 different websites, it would still be seen as duplication.
Overtime if i have success with the top 100, i will add another 100 or so every month.
Nothing wrong with that at all.
When it comes to SEO you basically have 2 choices. Either cheat the system and likely see great gains for a short period of time (black hat) or you can focus on offering excellent, unique value and an experience that users want to return for (white hat). Content spinning & copy/pasting from multiple websites definitely falls under the "cheat the system" category.