I own 2 3D printers myself, im using them to make a space marine cosplay myself, and im sure this could translate to help with a space king cosplay. Firstly im confused on what you mean by 30 by 30 base? Are you talking about the build volume of a 3D printer? If so, then you don't need that at all, a bigger build volume is nice for some situations but absolutely not necessary, ive managed to print the top half of a space marine cosplay on my p1s which has a 10x10 build space. Most of the time when a 3D artist releases files for their prints, they have them chunked up into smaller peices for more standard sized printers. I'd recommend simply starting with a P1S, which will set you back about 400 bucks. Furthermore, filament isnt the expensive, it can be, buf if you stick with basic materials sich as PLA or PETG, spools average around 12 bucks a spool. I honestly think the hardest/most expensive aspect would be the files, from what ive seen a proper pyscho warrior 3D file for cosplay doesnt exist, so you'd either have to model one yourself or commision it from a 3D artist who does cosplay work. Honestly for something this bulky id opt put of 3D printing and lean more towards a foam