If it is a SFR single family, Condo, or Townhome you can use a Vacation home type of loan and only have to put 10% down. 

It is also common in commercial loans. 

My question is, when buying a home, do most here use big banks for loans?

@Samuel Metcalf- thanks   1) I would recomend getting a HELOC in place on your primary residence duplex  for  as much as  possible...this should be available for  free or a low  cost and the rate will be variable in the  8-11%  range ...prime rate +  margin of  1-3% ) ...the min payment is in interest only payment on outstanding balance   2)  use the heloc for the  remodeling  costs ...pay it down as  agressively as you can   3) on the  purchase of the investmenet  1 unit -  you are  allowed to put as little as 15%  of the price for your down payment ...the pricing you get for the loan will improve  as your down payment  grows so you might look at  75% /  80%  and  85%  ltv  options 

I am currently up a little more than $100k on my current home an I have an FHA loan on my current home.

Luckily bank agreed to make repairs needed to pass four point.I had to get a renovation loan insurance policy where I paid for a year up front in escrow and they would pull $400 a month till renovations were completed and then I could find a new insurance policy and the remaining escrow would be transferred to the new policy.Paid $540 for an appraisal.

Due to inexperience opted for a 10 year loan which is going to clear in 4 years.

I'd estimate 12-15% of the sales price as you'll have to back out land value and then you'll get closer to 20% of actual home as a deduction (assuming 100% bonus depreciation which the jury is still out on that being extended. 2.

I chose the creative finance path because I started out as a loan officer bailing out pre-foreclosures, which you could do back in the day. 

@Craig JonesMost private lenders will want 10%+ return so you mix the loans and you mine as well refinance it at today’s rates.