As @Kay Kay Singh said, there are a lot of factors to consider, but ultimately you're looking to confirm that there will be future demand for your investment and you're buying at a number where you can make desirable returns both today and in the future.We have specific metrics for our investors such as IRR, cash on cash, equity multiple, etc.

@Seth Alexander I see this is your first post so welcome to BP.How to invest depends on a lot of factors.

It needs to have credit score (if reason) or others factors (active collections, etc.) and name and contact info for the credit bureau used. 

The other factor is opportunistic price increases.

I can lead when needed and will forever be a student of life.

What options do I have than to save forever?

The reason no one can give you a firm amount is because PMI fluctuates according to a bunch of different factors.

It took forever for the market to make it not underwater from the crash. 

Even though I love my mom, I don't want to be living in her house forever lol. 

Many different factors such as current expenses, condition of the property, additional revenue opportunities, surrounding neighborhood/surrounding rents.