jdrott,

You can use the If and the Mid command for this.

As you are familiar with VB6 it is the same as that.

Cor

I doubt you really want to do what you say.  I'm not sure which
character you think is in position 2, so I assumed it is the '3'.  You
probably don't want to assume that the decimal point is the second
character, use _str.IndexOf("."c) to find out where it is.  You
probably also don't want the second Substring call in the last line
which keeps the digits beyond the one that is changed.

Dim _chr As String
Dim _index As Integer = 2
Dim _str As String = "5.39"

If _str.Substring(_index, 1).ToInt32 <= 4
   _chr = "4"
Else
  _chr = "9"
End If
_str = _str.Substring(0, _index) + _chr + _str.SubString(_index + 1)

Why do you have the number in a string? As what you want is a numeric
operation, convert it to a number.

Dim price as Double
price = Double.Parse(theString)
price += 0.01
price *= 2
price = Math.Floor(price)
price /= 2
price -= 0.01

Use price.ToString("0.00") to create a string in the same format as the
original.