I am currently ready to list my flip house but I want to try doing it for-sale-by-owner first before I list with a realtor. I would like to know if there's a certain company I should use to get me on the MLS which also gets me listed with realtor.com and Zillow. I would like to just pay a company one flat fee to list with the MLS or is there a way I can do it on my own without any fees? Any help would be greatly appreciated.

There are many companies that offer to list you on the MLS for a flat fee. Simply google "Flat Fee MLS" + your city and you'll likely see them. You cannot list on the MLS without going through a licensed agent.

Prior to paying any money, be sure to read the listing contract that the company will ask you to sign. Also check their reviews.

I would think this over.... Your realtor markets, networks with other realtors... Have your realtor do a marketing presentation. Maybe tell them you will use them if they comp you staging.... In my market, FSBO is seen as a chump move. You will still pay the buyers agent anyway... so what are you really saving, and unless you are REALLY familiar with laws, and conditions... sketchy. between my purchase and sale of my flip, my realtor EARNED that $. and I got way more than his fee in increased price, advice, staging, help....