I want to buy my first rental but the market here is way over-priced for decent units and rent rates lower than average.

See the diagram below.I recommend you turn the process around and start by selecting the tenant pool with the longest average length of stay.

I’m getting mixed signals on what the average rates are today for owner financing.

Based on my research there is a lower than average population growth and higher than average unemployment. 

Average stays 6 years. 

what part of tampa, are they 2 bedroom units with room to increase rent (looks like your average rent is 950 a month/unit)

High risk, but potential for a more lucrative investment.I've reached out to a couple airbnb hosts in the area to see what they are averaging for monthly income on similar units (1950's build and updated interiors), and the range is $2,000-$2,600.

I under budgeted for the rehab and am now left with $100k in loans and credit debt at an average rate of 13.35%.

Average wholesale fee in Vegas is going to be about $2-$7k if you structure it right. 

So you have to ask yourself the question, why is one group getting $1900/month average and another is geting $7500/month average.