<prompt> Human: I know a lot of electronic purchases offer low interest monthly payments e.g. Apples Macbook Pros. Im curious if theyre ever a good idea - do people on PF ever use them? Or is it always better to save up and purchase in one go.  <response>: If its 0 or extremely low interest, and theyre not jacking up the price to offer that interest rate, and you actually invest the money you would have dropped in a lump sum, the math shows that it can be advantageous.Those conditions are fairly rare for me, so I just buy in one go, with the exception of a house. 