Amazon Web Services provides a calculator that you can use to estimate your monthly cost.
Here are some things to consider:
Reserved instance vs. On-demand instance vs. Spot instance.
- If you will be running the instance for a short period of time, but you require a degree of stability, go with an on-demand instance
- If you want to run the instance for a short period of time, but do not require stability (e.g. if it runs for just a few hours, or doesn't start until later, that is fine) - go with a spot instance. These usually have a price comparable to the medium-utilization reserved instances, but the price fluctuations are significant. Trying to outbid these fluctuations usually results in a higher bill than simply using a reserved instance.
- If you plan to run the instance for an extended period of time (months) look into the reserved instances. They have a (non-refundable) up-front fee, but significantly lower your costs, while improving the stability offered by the on-demand instances.
EBS vs S3 root device
- An EBS root volume offers much more versatility - the data persists even after the instance terminates, the volume can be transferred between instances, it is easy to backup (snapshot), etc. However, you must pre-allocate your EBS volumes (and are charged for the allocated space, not the used space) and you are charged for I/O as well. (You are probably looking at 2-3 IO/s and at least 5GB)
- S3 root volumes are cheaper - no cost for storage or I/O - however, they are ephemeral. Data saved to them will be lost when the instance terminates, you cannot easily back them up (e.g. if you update some software, that change will only persist if you create a new AMI), and they are generally not recommended.
- Incoming bandwidth is free
- You are charged for outgoing bandwidth (first GB is free)
- You probably want one (it is a static IP) and it has no cost, as long as it is attached to your instance. Keeping the IP address reserved but not attached to any instance has a cost associated with it.
Keep in mind that a static website (without the IRC part) can be hosted from S3 without the need for EC2. Naturally, this is a far cheaper alternative to running an EC2 server.
As an estimate, you are likely looking at between $13/mo (with a reserved instance) to $20/mo (on-demand) if you use a t1.micro.
As as estimate (us-east-1):
- 5GB EBS + 3 IO/s = $0.10/GB/mo + $0.10/million IO = $6 + $9.46 = $15.46
- 2GB outgoing bandwidth (1GB you are charged for) = 0.12/GB = $1.44
On-demand: $0.02/hr = 175.20
- Yearly total: 192.10; Monthly total: $16.01
Heavy usage 1 year reserved: $62 + 0.005/hr = $105.80
- Yearly total: 122.70; Monthly total: $10.23
Heavy usage 3 year reserved: $100 + 0.005/hr = $231.4 (for 3 years) = 77.13/year
- Yearly total: 94.03; Monthly total: $7.84
Depending on your needs, you will likely want to backup your EBS volume(s) with snapshots. Snapshots are compressed and differential, so a single snapshot should be smaller than the used data on your EBS volume. Storing many of them, however, can add up. 3GB of snapshot data will add about $0.40/mo to your bill.
(The cheapest version would be an S3-backed t1.micro, 3-yr reserved, heavy utilization instance - you cannot change instance types if you reserve, but you can change AMIs (including whether or not the instance is S3 or EBS backed).