Interest only mortgages
This is an arrangement where you're only paying off the interest on the loan.
Unlike a repayment mortgage you are not paying off the capital debt part of the mortgage.
So the mortgage costs you less which means you can borrow more.
But this idea that you can pay less is only a short term solution because you are supposed to set up a side by side investment because...
...the capital debt part must be repaid by the end of the mortgage term by your having made simultaneous monthly payments into a separate investment plan.
The idea is that this investment plan has hopefully grown enough to pay off the capital.