Follow these steps to purchase a reserved instance:

1. Go to the EC2 web console, select Reserved Instances, then Purchase Reserved Instances:

2. We now need to perform a search for the instance type that you wish to purchase. In this example, we're going to choose the following:
   • Platform: Linux/Unix
   • Tenancy: Default
   • Offering Class: Standard
   • Instance Type: t2.micro
   • Term: 1 months-12 months
   • Payment Option: All Upfront

3. Obviously, choose the options that best match your workload. You almost certainly want to choose Default as Tenancy here. Dedicated tenancy/instances are run on hardware that will be occupied by only one customer (you) and are a lot more expensive:

4. The console will return a price for the instance reservation. Note that because we didn't select Only show offerings that reserve capacity, what we are seeing is a single result, that is, a reservation that applies to the region we're currently viewing in the console. Think of this as a region-level reservation:

5. Now try selecting Only show offerings that reserve capacity and note that all availability zones are showing for the current region. You can think of these as AZ-level reservations. Choosing one of these options obviously locks you in to a specific availability zone; however, you also get a capacity reservation:

6. Choose the reservation that looks right for you, and then click Add to Cart and then View Cart.
7. The next page shows a summary of your imminent purchase. Click Purchase to proceed. Note that this is the point of no return. Reserved instances can't be canceled. Choose wisely!

Reserved instances are an invaluable tool to lower your overall AWS usage charges. Carefully analyze your EC2 usage, or use a tool such as Trusted Advisor to help with recommendations for making reserved instance purchases.