Monitoring services is a most but their fees are too high considering this:

Alternate hosting: monthly fee $6:00 with SSH & cron jobs BW 30 GB/m DS: 1 GB, upgradeable

Monitoring service, resolution (minutes), monthly fee (USA $) for one service:
Alertra $59,95, 1 min
hiperspin $12,00, 1 min
setuptime $5,00, 5 min
serviceuptime $4.95, 3 min
alternate host $6.00, 1 min, lots of services

You can set up a monitoring script as a cron job, monitor several services for several sites and could use it as a backup host for emergencies, extra email server, etc. Each site would monitor the other

Something to consider