First off each image you post is pretty much way too small.
To display numbers in a message box, here are three variations.
Private Sub DisplayNumberButton_Click(sender As Object, e As EventArgs) _
Handles DisplayNumberButton.Click
Dim oilChangePrice As Double = 39.99
Dim lubePrice As Double = 20
MessageBox.Show($"Oil: {oilChangePrice:C2} Lube: {lubePrice:C2}")
MessageBox.Show($"Oil: {oilChangePrice:C2}{vbCrLf}Lube: {lubePrice:C2}")
MessageBox.Show(
$"Oil: {oilChangePrice:C2}
Lube: {lubePrice:C2}")
End Sub