I have interviewed a couple of services, but I am not having any luck finding a reliable and affordable company.  

So, look for a 4-plex you can afford, or wait until you have the cash because even if you wait you will be far ahead.Before you invest in a single-family or multi-unit send a PM and I will do the math for you.

What kind of property can you afford to buy? 

You'll have to pay for the new LLC and the closing, but quit claim transactions are pretty affordable.

With that in mind, there is also less of a risk that you'll no longer be able to afford the investment property. 

If you are getting a mortgage, get a pre-approval in place now so you know what you can afford when you approach an investor-friendly realtor.

I want to know how much I could afford for the second house, because that will determine how much I actually spend on the personal residence property.  

I am 19 years old and I can afford a little more risk as I obviously have some time before I am going to retire.

Due to how expensive it is here, I am open to pretty much anywhere in Florida that I can afford and makes sense financially.

My bigger concern is whether she can actually afford the rent long-term, or if any "unexpected" event from here on out will put her further behind.