Spot instances are good for short term requirements as they can be very economical. However,
you may find that the instance is terminated if the spot market price moves
On-Demand is the best choice for this situation as it is the most economical option that
will ensure no interruptions
Reserved instances are good for long-term, static requirements as you must lock-in for 1 or
3 years in return for a decent discount
Dedicated instances are EC2 instances that run on hardware dedicated to a single customer