And of course, spending time here on the site. 

I am looking to spend $300-$350 on a multi unit.

Hey guys, I recently listened to the newest podcast (327) on BRRRR investing and I realized that there's one thing that I don't understand.Let's say you buy a 50k house.The house is trashed and you have to spend 30k fixin it up.This makes your total investment 80k.The house has now appriciated in value (thru forced appriciation) and is now worth 120k.You then find tenants (a family) and they are now renting it out for 1k a month.After this you go to the bank and refinance the house that is now worth 120k so you get a loan 75% of its value which is 90k.Now you get all of your capital back + 10k more, but the thing that I can't really understand is that THIS 90k is a LOAN and you have to pay interest on it right?

HELOC is great if you intend to pay it down sooner than later - keep in mind that with a HELOC the interest will fluctuate over time (and jump a lot after the introductory period), and it can be called by the bank (ie: closed) at any time - it happened to us in 2009 after the last market bust and we had to scramble to get approved for another one by another bank.

Spend the time to put your test ads out there on every platform you can. 

The numbers didn’t look all that bad for face value, but I did not spend time analyzing all the qualifiers. 

Any energy you spend on this will be easier than a drawn out eviction, so figure out the barriers and help them solve them.You may struggle to find quality tenants and folks that won't smoke in units, I had to really adjust my expectations over the years. 

It may vary in different markets as I know that @James Wise said expect to spend 25% down.

if seems like this is more of a hobby, i suggest spending your money on some of these reia events, get motivated and educated and then take action

They use the 4% rule (25 x annual spending), to determine when they can retire early and live off investment income.