Just as a summary in case this thread gets brought up again: Having an S corp on earned income (comissions, sales, flips, wholesaling) Can save on payroll taxes, however I don't typically recommend it if earnings are under about $70k. 

Also check with your friend or extended family, some of them might have funds that they don't need sitting in a savings account earning less than 1% interest.

REI earnings have been exponential!!!

If you aren't in the position to do either get out there & earn some extra income until you can.

And there is certainly the REI equivalent of that person, but they are not a newbie ... they have the experience, scale, and funds to do that, and that was earned first by operating locally.

., former employer 401k) to a solo 401k are not reported on Form 5498, but rather on Form 5500-EZ, but only if the air market value of the solo 401k exceeds $250K as of the end of the plan year (generally 12/31);When funds are rolled over or transferred from an IRA or 401k to a self-directed IRA, the amount deposited into the self-directed IRA is reported on Form 5498 by the receiving self-directed IRA custodian by May of the year following the rollover/transfer.Rollovers (provided the 60 day rollover window is satisfied) from an IRA to a Solo 401k or self-directed IRA are reported on lines 15a and 15b of Form 1040;Pre-tax IRA contributions on reported on line 32 of Form 1040;Pre-tax solo 401k contributions are reported on line 28 of Form 1040;Roth solo 401k funds are subject to RMDs;A Roth 401k may be transferred to a Roth IRA (Note that from a planning perspective, it may be advantageous to transfer Roth Solo 401k funds to a Roth IRA before turning age 70 ½ in order to escape the Roth RMD requirement applicable to Roth 401k contributions including Roth Solo 401k contributions and earnings.)

Could there be something more distinguishing for you to spend your hard earned money in?

You can hire someone insured to do demo for $10-15/hour...unless your goal is to earn $10-15/hour in the flipping business, hire it out, as that's what you're earning while you're swinging a hammer...The more important question is what you should be doing during the time you're not swinging a hammer. 

What's your earned (W-2) income look like and do you plan to K-1 earnings from your business? 

If you do a 3-5 year call (the date on which you owe him all the money), you would theoretically have enough in the bank account from the earnings of the property to fund the down payment and get a traditional loan (commercial loan, in this case).