Finally completely done, my bandos godsword replica from Runescape 3!
I mainly used the concept art as reference, and made it about 155cm tall (5ft), almost equal to the length of the sword ingame compared to your character. It's very heavy, i think atleast 5kg (11lbs)!
It is made from a wood base with cardboard skeleton and cardboard/foam/woodfiller to fill it up, with worbla details, and latex as a priming base. Painted with acrylics and finished it off with spray varnish to keep it nice. The handle is wrapped suede.
Fabricating costs? Hard to say, almost all of it is leftover stuff, except for 1eu for a piece of suede. If i bought all the materials first hand it would be 5eu for the wood, 10eu for priming and painting supplies, 5eu for a bit of worbla, 1eu for suede fabric, 4eu for glue, 1eu some sandpaper (although alot of it is done with a dremel, which is 30eu tool, i also used a precision saw to cut out the wood base). So that makes for a total of around 30eu for raw materials.
pic of the shape i cut out of wood (the sword was too big so the handle has an extra piece glued and taped to it that was cut out seperately):
just cardboard (horns and rings were attached later)
Almost ready for painting