You can look for Paradox prices, for Chelydra it be the same, now +200-1000 PED per part.
When i started collect Chelydra M, i bought Gloves +960, Thighs +600, Harness for TT+1,5k
But this was more than 1 year ago, now prices drop down. And i bought these parts for Kreltin and Longtooth only, because this armor has very specific Protection...
Yes it very rare, but...you can find Angel Harness for TT+3k and your mob choice will be a much broader