You certainly don't need to have an expensive jig. You don't even need to have an Oxy-Acetylene welding rig. You can get by with a few files, a hacksaw and some Mapp Gas, but you do need to learn how to use them.
Also, read this book:
Lugged Bicycle Frame Construction Manual First Time Builder by Andre Chimonas
It's not about the kit, it's about the skill.
You certainly don't need to have an expensive jig. You don't even need to have an Oxy-Acetylene welding rig. You can get by with a few files, a hacksaw and some Mapp Gas, but you do need to learn how to use them.
Also, read this book:
Lugged Bicycle Frame Construction Manual First Time Builder by Andre Chimonas
It gives the most accessible overview available.