Credit is not an evil entity out to destroy your life and your family. It is just the ability to buy or obtain items without having to produce the cash at the moment of the transaction. The presumption is that the cash is available to pay off the items.
Many people have confused the purpose of credit and have allowed it to become debt. Purchases are made without the backing of the cash and instead are paid off over several months. Although this helps with the need for instant gratification it raises the costs of many products to almost double (because of interest that is incurred on the items).
To use credit properly the charge must be paid in full before any interest starts adding up. That means that there needs to be cash available to make the payoff (usually in a savings account).
You can also use credit to decrease the cost of items particularly when you can secure a long term of no-interest financing. Leave your money in the savings account making interest and use the credit to make the purchases. The key to making this work is to pay off the sum in full before the interest starts up.