save (an amount of) (money) on (something)
To conserve or avoid spending (an amount of) money on something. You could save on your electricity bills if you stopped running the air conditioning so often. I saved over $200 on my flights by using this discount service. I'm hoping to save some money on a new computer during the Black Friday sales.
save (money) on something
to save money or some amount of money on the purchase of something. I can save a lot of money on this purchase by buying it somewhere else. I am sure you can save on a new car if you shop wisely.
1. To conserve money by purchasing something at a discount: Save on all kitchen appliances during our special clearance sale!
2. To conserve some amount of money by purchasing something at a discount: I saved a dollar on my purchase by using a coupon.