We have AmazonAWS t2.micro server (free tier). T2. micro has 1 Gb of ram and 1 vCPU. Only CiviCRM (4.7.14) is hosted there along with its Drupal.
Currently the database is very small (less than 5000 contacts). Once a day we request Cron to email 6-8 reports (e.g., all contacts, contributions in last 3 years, etc.). The summary daily traffic seems to be below 10Mb. Other than that there are some Smart groups (100-200).
With this setup MySQL is sometimes running out of memory. Could it be wrong settings or 1Gb is just not enough?