using System;
using System.Text.RegularExpressions;
using System.Linq;

public class Test
{
	public static void Main()
	{
		string pattern = @"(?<=^(?:[^$]*\$){0,3})[^$]*\$?|[^$](?=\$|$)";
        string[] strings = { 
            "Text1",
            "Text1$Text2$Text3",
            "Text1$Text2$Text3$Text4$Text5$Text6"
        };            
        
        Regex regex = new Regex(pattern);

        foreach (String s in strings) {
            Console.WriteLine(string.Join("", from Match match in regex.Matches(s) select match.Value));
        }
	}
}