Check the Course Date Price Schemes - is the cost you’re seeing in SB3 against any of these mappings? If so, check the eligibility of the Price Scheme against the user creating the basket (Accounts/Account Group/Job Roles against the user that is logged in who is creating the SB3 basket.).
If not, check the Course Template Price Schemes - is the cost you’re seeing in SB3 against any of these mappings? If so, check the eligibility of the Price Scheme against the user creating the basket (check the Accounts/Account Group/Job Roles against the user that is logged in who is creating the SB3 baskets).
If there is no Accounts/Account Group/Job Role selected for a Price Scheme, then by default this cost will apply to all bookings.