This will drive more traffic, as there are many self-employed or people wanting to buy but held back by previous foreclosure/BK timelimites, divorce, etc hampering them from getting traditional financing, and if you're wanting to rent it again quickly, and sell eventually, this would be a good strategy for maximizing your cashflow during the turn.

There are several out there that cover the basics, and then you can add on items like a hot tub.  

With traditional sales it’s earnest money that goes hard at a specific point in time.

@Redha Laafia you can also talk to sub-contractors  and develop a price list for items like roofing, painting, kitchen and countertops, flooring etc. those are very easy items to standardize. 

Be sure that you highlight that "selling your house can be easier than you think" with the advantages of working directly with you instead of the more traditional route.

those items can come into play as your portfolio expands.to start, simply find find a decent property that isn't too overwhelming and learn by doing. 

Compared to an IRA, Solo 401k contribution limits are roughly ten times higher.There is no custodial requirement for the 401k.You don't need the additional expense and administration of an LLC to have checkbook control.There is a built in-Roth component whereas IRAs are either traditional or Roth, not both.A spouse can also participate in the same Solo 401k plan.The Solo 401k has additional tax benefits over an IRA when investing into real estate using leverage.You can borrow from a 401k, but not an IRABoth C-Corps and LLCs can adopt a Solo 401k.

I have not discussed comparable building specs with a traditional builder, yet. 

I used traditional financing and partnered with a friend on the cash to close.

You might be able to do the HELOC... but My guess is your rate will be much lower with a traditional cash out refi.