There is no need to suspend your service - GigSky does not charge a monthly fee. You only pay for the data plans that you purchase and they don't automatically renew.
However, each individual data plan has a validity period, for example 30 days. Once you have started using a plan, you can't put it on hold and start it again at a future date. It will expire after the published validity period and any unused data will be lost once that period expires.