You will spend more if you use credit cards. Even by paying the bills on time, you are not beating the system! But most families don't pay on time. The average family today carries $8,000 in credit card debt according to the American Bankers' Association.
Now let's talk about the rebates. If you were using a credit card at 5%, you would have had to have spent $80,000 to get $4,000 rebates on new cars that lost $6,000 of value when you drove them off the lot. That is not a good deal!
When you pay cash, you can "feel" the money leaving you. This is not true with credit cards. Flipping a credit card up on a counter registers nothing emotionally. A study of credit card use at McDonald’s found that people spent 47% more when using credit instead of cash. This is money you could have saved!
If you "have to" use plastic, I suggest a debit card. I use them for travel and the occasional convenience of ordering something over the Internet or phone. Other than that, I use cash.
Personal finance is 80% behavior. You need to cut out habits that make you spend more. You do not build wealth with credit cards. Use common sense. When you play with a multi-billion dollar industry and you think you're going to win at their game, you are naive. You cannot beat the credit card companies.