In the past, I've just hired it out if I'm not comfortable with the situation. 

I am about to buy my first property BUT ever time I try to run the numbers I do not feel comfortable giving an estimate of repairs but I also do not know who to ask.

If you can qualify comfortably and are willing to take the risk, then jump.Another option is to get into contract to purchase the new house, close and then sell the existing one which mitigates (reduces) the risk of owning two properties in a market that may decrease in value.

Then the other PMs will say, well-- you're used to paying $900/mo, so it should be a comfortable financial fit!

Ive heard good things about Comfort Experts

Often I go in and spray foam insulate as soon as possible which may cost me $7-10,000 but will not only save me oil money but will keep the units more comfortable year round and cooler during the summer keeping tenants electricity costs down for their A/C.

@Jordan Childs do you self manage or are you running a property management company?

The more you can learn up front the better a decision you can make and the more comfortable you can be on the price you are offering.

The entire real estate agent model is at threat over time as younger generations are comfortable with using technology to buy and sell anything. 

While you want to minimize the financing costs, it also has to be worthwhile for your HML, so you might consider using $100k in hard money, then using your HELOC and/or cash (in whichever order you're more comfortable with) for the rest, keeping enough in reserve for the repairs and renovations.