The average refrigerator price/cost obviously varies depending on what features are required. However, for a standard-sized refrigerator, the average price range is $400-700 depending on features, material, and size/storage capacity. Some larger, wider refrigerators will be more expensive, however, not necessarily.
It's also worth mentioning that refrigerators are usually durable goods, and so they last for many years. When they break down, they can often be repaired for less than the cost of replacing them. For this reason, it is often popular to buy or sell them second hand, particularly on Craigslist.