Laser welding: I recomend this guy

[MEM62]

At what point is laser welding a cheaper or better alternative to buying a new/used part?

How do you even work it out ?

It's not always about cost, sometimes it's about availability.  Just try buying a float bowl - you can't!  When a Yamaha dealer cracked one of mine during a service the only option was to buy a whole carb at some extortionate cost.  I ended up buying a set of used carbs off evilbay just to raid a float bowl from as it was about a third of the price of a new carb from Yamaha.  Unfortunately, although the damage to mine was similar to the OP's, I could not find anyone to weld it.