Spot instances best practices
Build Price-Aware Applications
Check the Price History: In general, picking older generations of instances will result in lower net prices and fewer interruptions.
Use Multiple Capacity Pools: By having the ability to run across multiple pools, you reduce your application’s sensitivity to price spikes that affect a pool or two (in general, there is very little correlation between prices in different capacity pools). For example, if you run in five different pools your price swings and interruptions can be cut by 80%.