Friulis aren't that hard to assemble, just sometimes alot of clean up.
Basically have to run a drill bit in a pin vice through all of the attachment holes to clean out any metal flash, then it is just cut the wire to length that you need per link attachment, and put it together.
Some people opt to instead of using the supplier wire (as it is kind of soft) to buying a box of straight pins (any dept. store with a sewing/material section) as they are stronger than the soft wire, and the flat head of the pin gives you a nice track pin head, slide it through cut off the excess. The downside, is that they are harder to cut then the soft wire that comes with the tracks.
As far as investment wise? Depends on the kit really, that one you have is probably a good candidate for Friulis.