[Buying]  Left String Launcher BURST

Ayy I'm looking to buy a left spin string beylauncher for Burst, the one that comes with Longinus, because i took mine apart and couldn't put it back together, I'm an idiot. Should i just buy one from samurai buyer for waay overprice(20 bucks) or can someone here hmu
For 20 bucks you can buy Lost longinus of eBay why not get that.
I think I remember one that comes with lost for 20$