Availing discounts from time to time is not bad. On sale items are not all time substandard and sometimes buying items on sale could allow you to save up bigtime. Every time you shop, see to it that your goods are in good condition. Check for expiration dates for edible items, any defects, etc.
There are cases wherein you are having your shopping online and you can’t simply do all these things, then it’s a bigger risk this time. See to it that you warranties so then whenever the goods are not in good condition when it arrives, you can demand for a refund. Do not just place anything inside those computer carts without reading anything from it.