db.t3.medium is an Amazon Neptune size with 2 vCPUs, 4 GiB memory (Variable). In US East (N. Virginia) it costs $0.098 per hour on demand ($71.54 per month) for Standard storage. It is sold in 31 regions.
Prices by region
USD per hour, Standard storage. Reserved prices are no upfront, standard. Cheapest on-demand first.