For Verizon pre-paid data plans, once you activate your data plan, you can cancel the plan at any time.
However, you have two options:
Delete account now vs. Delete account later.
Delete account now means - immediately cancel your 4G/3G service, deactivate the SIM card. You'd have to get a new SIM card if you wanted service again.
Delete account later - cancel autorenew. Your data service lasts until the end of the billing cycle, and you are not charged for a new month of data. Your SIM card is fine, and you can sign up for 4G/3G service in the future. However, if you do not reactivate the 4G/3G service within 5 months, the SIM card is deactivated, and once again, you'd have to get another SIM card.
Hope this helps you out. 🙂