Thanks guys for the help, I found a free app to hide cost price by Cybrosys Techno Solutions
for the sale price I have tried to do the same thing but it did not work here is the code and the error I am getting if someone can help:

/security/hide_sell_price_groups.xml
<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <data>
        <!-- Access to the sell price -->
        <record id="groups_view_sell_price" model="res.groups">
            <field name="name">View Sell Price</field>
            <field name="users" eval="[Command.link(ref('base.user_root')), Command.link(ref('base.user_admin'))]"/>
        </record>
    </data>
</odoo>

/views/product_product_views.xml
<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <!-- Product Variant Form View -->
    <record id="product_normal_form_view" model="ir.ui.view">
        <field name="name">product.product.view.form.inherited.hide.sell.price</field>
        <field name="model">product.product</field>
        <field name="inherit_id" ref="product.product_normal_form_view"/>
        <field name="arch" type="xml">
            <field name="lst_price" position="attributes">
                <attribute name="groups">hide_sell_price.groups_view_sell_price</attribute>
            </field>
        </field>
    </record>
    <!-- Product Variant Tree View -->
    <record id="product_product_tree_view" model="ir.ui.view">
        <field name="name">product.product.view.tree.inherited.hide.sell.price</field>
        <field name="model">product.product</field>
        <field name="inherit_id" ref="product.product_product_tree_view"/>
        <field name="arch" type="xml">
            <field name="lst_price" position="attributes">
                <attribute name="groups">hide_sell_price.groups_view_sell_price</attribute>
            </field>
        </field>
    </record>
    <record id="product_variant_easy_edit_view" model="ir.ui.view">
        <field name="name">product.product.view.tree.inherited.hide.sell.price</field>
        <field name="model">product.product</field>
        <field name="inherit_id" ref="product.product_variant_easy_edit_view"/>
        <field name="arch" type="xml">
            <field name="lst_price" position="attributes">
                <attribute name="groups">hide_sell_price.groups_view_sell_price</attribute>
            </field>
        </field>
    </record>
</odoo>

/views/product_template_views.xml
<?xml version="1.0" encoding="utf-8"?>
<odoo>
    <!-- Product Template Form View -->
    <record id="product_template_form_view" model="ir.ui.view">
        <field name="name">product.template.view.form.inherit.hide.sell.price</field>
        <field name="model">product.template</field>
        <field name="inherit_id" ref="product.product_template_form_view"/>
        <field name="arch" type="xml">
            <field name="lst_price" position="attributes">
                <attribute name="groups">hide_sell_price.groups_view_sell_price</attribute>
            </field>
        </field>
    </record>
    <!-- Product Template Tree View -->
    <record id="product_template_tree_view" model="ir.ui.view">
        <field name="name">product.template.view.tree.inherit.hide.sell.price</field>
        <field name="model">product.template</field>
        <field name="inherit_id" ref="product.product_template_tree_view"/>
        <field name="arch" type="xml">
            <field name="lst_price" position="attributes">
                <attribute name="groups">hide_sell_price.groups_view_sell_price</attribute>
            </field>
        </field>
    </record>
</odoo>

and here is the error

odoo.tools.convert.ParseError: while parsing /home/odoo/odoo18/custom_addons/hide_sell_price/views/product_template_views.xml:4
Error during parsing or validation of the view:
The element <field name="lst_price"> cannot be located in the parent view

{
  "file": "/home/odoo/odoo18/custom_addons/hide_sell_price/views/product_template_views.xml",
  "line": 1,
  "name": "product.template.view.form.inherit.hide.sell.price",
  "view": ir.ui.view(3570,),
  "view.model": "product.template",
  "view.parent": ir.ui.view(470,),
  "xmlid": "product_template_form_view"
}

If you have the Studio app installed (extra cost): 

Open the view with fields you want to restrict access.  Open studio.  There click on the field.  On the left side down, you will see 'Limit Visibility to fields'.  Careful, you can mess up.  I recommend you know the basics on managing access rights.

The result is a code like described by Chris.

The studio app then adds an extension view that is inherited in the basic view.   You avoid modifying Odoo standard code.

Studio app is excellent for those that do not know coding. But comes with a warning: You can mess up, and this might not work after updated version.