One of the biggest expenses of owning a new car is actually one of the easiest to eliminate. It's not insurance or gas -- it's depreciation. According to AAA, depreciation accounts for almost 40% of of the cost of a new car, roughly $3,000 a year. So if you'd like to add another $3,000 to your savings account every year, buying a gently used car is one of the smartest moves you can make.

In recent years, an influx of cars coming off lease are deeply discounted and provide bargains for used car shoppers, according to auto search engine iSeeCars.com, which analyzed more than 4.8 million car sales to identify models with the greatest loss in value after three years, when most leased cars enter the used car market.

The average vehicle depreciates 38.2% in that time, according to iSeeCars, while these highest-depreciating vehicles lose more than half of their value, resulting in significant savings for savvy shoppers opting to buy a used car in favor of a new one.

These are the best bargains on lightly-used cars under $20,000, followed by the best 3-year-old SUVs, electric cars, and luxury cars to look for.