Firstly all that string concatenation is messy - have a look at
Using the StringBuilder Class in .NET | Microsoft Docs[
^] it will be far easier to follow your code and you will only assign to the textbox once
Secondly - The total amount - add it up as you go (not sure why you have used hard-coded amounts) then add a line for that at the end
Edit - something like this (note - this is untested) and there are even better ways of doing this
Dim sb As StringBuilder = New StringBuilder("YOU HAVE ORDERED:" & vbNewLine)
Dim totCost As Double = 0.0
sb.Append "ROOM TYPE" & vbNewLine & "--------" & vbNewLine
If radLuxury.Checked Then
sb.Append "Luxury = $210" & vbNewLine
totCost += 210
ElseIf radSuperior.Checked Then
sb.Append "Superior = $150" & vbNewLine
totCost += 150
Else
sb.Append "Standard = $110" & vbNewLine
totCost += 110
End If
sb.Append vbNewLine & "Total Cost: " & totCost.ToString()
lblTotalCost.Text = sb.ToString
Also have a look at
https://www.dotnetperls.com/format-vbnet[
^]