If taking out a loan is unavoidable, try to make as big of down payment as possible. The more of the cost of the purchase you can cover up front, the quicker you'll pay off your loan and the less you'll spend on interest.
While everyone's financial situation differs, most banks recommend that your debt payments should be about 10% of your pretax income, while anything under 20% is considered healthy. About 36% is seen as an "upper limit" for reasonable amounts of debt