Welcome to the community!
It would depend on the details of your current plan and whether it has enough (or any) subsidy attached for a new device. What plan do you have? If it is a BYOP plan, then it would not be possible to subsidise a phone without changing your plan since those plans do not have any subsidy. If your plan does have a subsidy, the amount of subsidy would determine the upfront cost of the new phone.
If you do not know your plan type, your My Account should provide your plan details. Alternatively, you might consider contacting customer support or sending a moderator a PM because they will need to access your account information.
Hope this helps