The effects of materialism are only negative.
The things you have on earth are only temporary. Now, whether or not you believe in an afterlife is your choice, but think logically.
Lets say there is a God, and you believe in Him, and you do your best to live your life by His standards. Only good can come of it. You don't treat your worldly goods like they are your master. You spend more time paying attention to your family, and making yourself into the person you want yourself to be. You don't let your materials own you and control you.
Outcomes:
a. You pass away, there is a God, you go to heaven. You have left the earth with only good thoughts behind you in your memory. Material goods actually dont mean anything.
b. You pass away, there is no God, your spirit sits in whatever realm may be out there. Your memory on earth is still good, and material goods still dont mean anything.