$500 via Verizon e-gift card (sent w/in 8 wks). Activation of 4G LTE/5G phone on One Unlimited for iPhone (all lines on account req'd on plan), 5G Do More, 5G Play More or 5G Get More plans req'd. Device must remain active for 45 days. $500 charge back if service cancelled w/in 12 mos or eligibility req's are no longer met. See vzw.com/bring-your-own-device for details.
You're not going to be charged on wifi or 3g regardless since a data package is required to have it active on a verizon line. You'll have to knowingly use something to be charged for it (i.e. Text messages without a texting package or using vz navigator instead of google nav)