db.m1.large is an AWS RDS size with 2 vCPUs, 7.5 GiB memory (Intel Xeon Family). In US East (N. Virginia) it costs $0.245 per hour on demand ($178.85 per month) for PostgreSQL, Single-AZ. It is sold in 9 regions.
Prices by region
USD per hour, PostgreSQL, Single-AZ. Reserved prices are no upfront, standard. Cheapest on-demand first.