Billing

Can i Bill just for an one month. Without auto renewal?

Yes, you can but you must have to cancel your subscription before the next renewal mean within the subscription month.

You are always open to cancel your subscription at any time: https://help.elements.envato.com/hc/en-us/articles/360000621563-Cancelling-Your-Subscription

Also note that subscription only for envato elements not for envato market. In Envato Market (as like themeforest, codecanyon ) there is no subscription service.