"cannot make the grade"= when the investor got a loan back in 2019 the rate was 4 and now at 8 -10 the rents no longer cover the payments.

So you figure 25k for a down payment equates to a property worth about 166k that will need maybe 75k in repairs let's say for a total project cost of 241k (loan amount would be 216k approx), then holding and closing costs of about 15k.Now when the project is over and you sell, you'd want to try and sell it for 241k/.70 = 340kish. 

@Jessie Cervantes DSCR loans require 25% down payment and are higher interest rate than a conventional 30 year note.

Jack Bosch and a lot of the land flipper guys who teach it like to have their students buying in the high deserts and remote areas of the Western US  or in FLA like le High Acres etc. this is were cheap land is and land that gets traded constantly at tax sales.. the play for most of them is really simple.buy at tax sale or with direct mail.. for a few grand  re-market them for more and sell on terms and collect monthly payments.. 

I've recently seen people giving advise to take out a HELOC as a means to pay your normal everyday expenditures including bills, and at the same time, taking your paycheck from job and applying it every month towards your mortgage payment.

I've been saving for the past year as much as I can and I've got about $20K to help with a down payment on the next property.

Does the down payment and income requirements make it difficult for first time or low income buyers?   

Joshua,  I understand your point of using the HELOC as 2nd which may be close to accomplishing the lowered total interest payments but in the end, anything you push toward your traditional is locked up and not easily accessible when opportunity knocks.   

Do note that only the mortgage interest that you pay is deductible, not the principal payments, but you'd also be able to take depreciation and possibly other expenses on the property such as utilities or maintenance.

Would reconsider in the future: -20% down payment.