To do this, one needs to save a relatively small lump sum of money that can be used as a base. (syndicatemortgages.com)
As for the smallest lump sum, I'd keep it relative to the commission charged. (thecollegeinvestor.com)
An adjustable rate enables the borrower to configure how and when the loan proceeds are disbursed such as: a line of credit, tenure or term monthly payments, a small lump sum at closing, or a combination. (reverse.org)