db.x2g.4xlarge is an Amazon Neptune size with 16 vCPUs, 256 GiB memory (AWS Graviton2). In US East (N. Virginia) it costs $4.377 per hour on demand ($3,195.43 per month) for Standard storage. It is sold in 4 regions.
Prices by region
USD per hour, Standard storage. Reserved prices are no upfront, standard. Cheapest on-demand first.