I'm trying to help my friend build a lightsaber and we're having trouble working it out. It seems there is different parts as well as crystals that can be used. I think we can build the parts but how do we get the crystals? Also, is it possible to use a Krayt Dragon Pearl?
Lightsabers can't be crafted right now, actually. Mikel is still working on the upcoming lightsaber crafting quest and details aren't known yet. At this time the only way to acquire a lightsaber in-game is to buy one from someone who already has one.
The question is, who would sell a saber in the first place? How much is one worth now though? I mean the technology says it does have a limit of credits, but right now, their rarity, how much could they be worth?
There was a period of a few months where there were constantly lightsabers listed on the market. Since so many force users had one when they could be constructed, and force users have been killed/gone inactive/sold their sabers, they're not especially rare in-game. Just depends on who wants to sell, these days. Couple hundred mil is probably in the ballpark but depends on the saber type (not to mention the value of credits, which is still fluctuating some).