im4gn.xlarge.search is an AWS OpenSearch size with 4 vCPUs, 16 GiB memory. In US East (N. Virginia) it costs $0.546 per hour on demand ($398.58 per month); a 1-year reserved instance with no upfront costs $0.377 per hour, 31% less. It is sold in 12 regions.
Prices by region
USD per hour. Reserved prices are no upfront, standard. Cheapest on-demand first.