AWS has a variety of discount programs available, if you can plan ahead for your computing needs. These are called “reserved instances” (vs. the regular on-demand instances for computing that you pay for as you need them). You can save a lot of dough if you plan ahead, ranging from 30% off up to 75% off for the larger resources.
There are three payment options available, making things a bit more complicated. With the All Upfront option, you pay for everything upfront, which as you might suspect gives you the biggest break. You can also pay something upfront, or nothing upfront, for lower discounts.