Using Ptil's Murex Snail dyed strings to make a set of Karaite sisith, would cost $225.00, for the strings, not including plaiting.  This is based on $45.00 for 5 meters of blue string, here.  Karaite sets require about 25 meters of blue.  A part of the higher cost is because the process of extracting the dye is lengthy and they are also making their blue wool strings by spinning the fleece they dyed and certifying the strings as Kosher.  

Using Radzin's Cuttlefish dyed strings to make a set of Karaite sisith, would cost $130.00 to 169.00, for the strings, not including plaiting .  This is based on $26.20 - $33.85 per 5 meters of blue string. here  Karaite sets require about 25 meters of blue.  The Radzin use Kosher wool string.

Using Spirulina Algae dyed strings to make a set of Karaite sisith, would cost $125.00 for the strings, not including plaiting.  This is figured at $25.00 for about 5 meters of blue string in one set, here.  Karaite sets require about 25 meters of blue.  A part of the cost is that the wool strings are purchased as certified Kosher.  The hemp and linen strings are spun there and then certified Kosher.

Using Woad dyed strings, to make a set of Karaite sisith, would cost $24.00 for the strings, not including plaiting, here.  This reflects more than 84 hours of work for 60 sets of blue strings.  This is to remove the oils and waxes on the strings and twice as much dyeing as before.

Using Indigo dyed strings, to make a set of Karaite sisith, would cost $6.50 for the strings, not including plaiting.  This vendor charges $31.11 per skein of 122 meters, here.  Karaite sets require about 25 meters of blue.  However this vendor charges $58.00 for a set of indigo dyed linen, 'Traditional Karaite tzitzits' making the cost of their plaiting at $51.50.  Note, these are stylized and not using the Traditional pattern and number of plaits. 

Israeli Karaites' Traditional Karaite tied sisith with synthetic dye use about $2.00 for the strings, not including plaiting.  However their cost for a set of Traditional Karaite sisioth is now 150 Israeli New Shekels or $46 here.  This has gone up from 80 Israeli New Shekels, 5 years ago. 

Plaiting or tying a set of  Traditional Karaite sisith, appears to range from $42.00 to $51.00 for plaiting only.  I could only find 2 other vendors selling Karaite sisioth now.  I am are charging  $ 24.00 or $12.00/hr for the 2 hours it takes to cut, plait and tie small knots on the ends of 128 strings. Both the large/gadol and medium/qatan have the same plaiting pattern and require the same amount time to tie. 

The sites where I gathered the prices from and then calculated for the differences in size, numbers of strings and other factors are listed here;

1. Ptil Murex snail

https://shop.tekhelet.com/collections/strings/products/raavad?variant=33551229943948

2.  Spirulina  

https://www.rivkasari.com/TZIT.html

3. Radzin cuttlefish   

https://www.ajudaica.com/Heavy-weight-Original-Blue-Tekhelet-Radzin/item690              

4.  Karaite with synthetic dye at the Israeli Karaite bookstore

http://www.karaitebooks.com/Page3_885885_Article-773.html

5.  Indigo   

https://www.zipporahreshel.com/product/indigo-skein-cotton/

Price comparison of candidates of hand dyed tekheleth at a glance;

This is a very brief and condensed comparison of the cost of the other candidates' tekheleth strings.  The comparison is made based on 4 blue strings per sisith, as would be needed for a set of four Traditional Karaite sisith, requiring 16 blue strings in all, 25 meters.  

These are the costs to use the same amount of blue string, 25 meters, to make a Karaite traditional set of sisith.   

Ptil Murex                      $ 225.00

Radzin Cuttlefish              130.00  

Spirulina                           125.00

Woad                                 24.00

Indigo                                  6.50  

Synthetic dye                       2.00

Charges for plaiting a set of four Traditional Karaite sisith on the internet range from about $44.00 to $51.50.  I could only find 2 other vendors selling Karaite sisioth now.  I am charging $24.00, which works out to be $12.00/hr. for 2 hours of work. Both the large/gadol and medium/qatan have the same plaiting pattern and require the same amount time to tie. 

So to compare only just the cost of tying a set of Traditional Karaite sisioth:

Tied by the Indigo seller @$25.75/hr.      $51.50 + $6.50 (strings) = $58.00

Tied by the Israeli seller @$22.00/hr.     $44.00 + $2.00 (strings) = $46.00

Tied by myself               @$12.00/hr.   $24.00 + $24.00 (strings) = $48.00