Do some reading here.
http://www.kragcollectorsassociation.../yabb2/YaBB.pl
The Krag section here.
http://www.milsurps.com/index.php
CMP has good Krag info.
and here.
http://www.surplusrifleforum.com/index.php
A original rifle can be found for around $500+. A true Carbine is double to triple and can go over 3K for the rare models.
I have a 1898 rifle and I'm looking for a 98 Carbine...at the right price. Everything I find is fake or over priced.