You buy the truck and depreciate over the same time .The truck technicality is now worthless to your business. And how much money did that truck make you in that time. And up here salt will eat your truck ,hard to keep a truck working for a long time. I just traded in a 2002 with 67k on it ,salt ate it.
Well hopefully after 5 years a 50K financed should "net" you 250000$, but I seriously doubt it can. Not to mention a 10k truck has the ability to preform the same duty as a 50k truck. At least you agree its a bad investment.