"Shark Tank" investor Mark Cuban says that his number one piece of money advice is to not use credit cards. The billionaire says it's the one thing he wishes he had known about money in his 20s: "That credit cards are the worst investment that you can make." » Subscribe to CNBC Make It.: cnb.cx/2kxl2rf About CNBC Make It.: CNBC Make It. is a new section of CNBC dedicated to making you smarter about managing your business, career, and money. Connect with CNBC Make It. Online Get the latest updates: www.cnbc.com/make-it Find CNBC Make It. on Facebook: cnb.cx/LikeCNBCMakeIt Find CNBC Make It. on Twitter: cnb.cx/FollowCNBCMakeIt Find CNBC Make It. on Instagram: bit.ly/InstagramCNBCMakeIt Why Mark Cuban And Other Famous People Don't Use Credit Cards | CNBC Make It.