You can't sell it, if you sell it, Nook gives you 1,7 million bells. 15 x 99,999 = 1,499,985
You can't hold that much!
Also info on the sabres:
5. Question: What are the BlueLightSabreV1 and RedLightSabreV1?
Answer: These Sabres are items that were made by creating an entirely new sprite image and utilizing the ability of an Axe. They both look like colored sticks. You can wield both of these Sabers like an Axe, and like an Axe, you can cut down trees. The BlueSabreV1 never breaks and has the pocket and dropping icon of a Gold Axe. You can try to sell a BlueSabreV1 for 1,700,000 bells; however, it is impossible to hold that much so Nook will not accept it. A RedSabreV1 is almost exactly the BlueSabreV1 but the pocket image is a near-broken regular Axe. A RedSabreV1 sells for 250,000 bells. Both items cannot be cataloged, as they function like tools and tools do not appear in your catalog.