Hi Steve,
The following code can meet your needs. The effect is as shown in the image:

Please note the parts highlighted in red in the image (not the effect of the code). These amounts also contain the aforementioned characters, but the $10 or $150 in them will not be highlighted because they are only part of the field. If you also need to highlight the characters in these amounts, you can let me know in your reply.
Here is the complete code:
Sub HighlightExactDollarAmounts()
Dim regex As Object
Dim matches As Object
Dim match As Variant
Dim rng As Range
Dim nextChar As String
Dim nextTwoChars As String
Set regex = CreateObject("VBScript.RegExp")
regex.Global = True
regex.Pattern = "\$(10|150|167,000|1,230,000)"
For Each rng In ActiveDocument.StoryRanges
Do
Set matches = regex.Execute(rng.Text)
For Each match In matches
If match.FirstIndex + Len(match.Value) < Len(rng.Text) Then
nextChar = Mid(rng.Text, match.FirstIndex + Len(match.Value) + 1, 1)
nextTwoChars = Mid(rng.Text, match.FirstIndex + Len(match.Value) + 1, 2)
If Not IsNumeric(nextChar) And Not (Left(nextTwoChars, 1) = "," And IsNumeric(Right(nextTwoChars, 1))) Then
Set rngFound = rng.Duplicate
rngFound.Start = rng.Start + match.FirstIndex
rngFound.End = rngFound.Start + Len(match.Value)
rngFound.HighlightColorIndex = wdBrightGreen
End If
Else
Set rngFound = rng.Duplicate
rngFound.Start = rng.Start + match.FirstIndex
rngFound.End = rngFound.Start + Len(match.Value)
rngFound.HighlightColorIndex = wdBrightGreen
End If
Next
Set rng = rng.NextStoryRange
Loop Until rng Is Nothing
Next
End Sub
I look forward to you sharing the results with me.
Best Regards,
Jonathan Z - MSFT | Microsoft Community Support Specialist