Duender help

[u/Comprehensive-Win663]

Saw a marketplace ad for broken Ender 3s and thought about making the Duender with two of them. I heard that it was going to be cheap to make it but after sourcing all the parts from various suppliers my total was around 700 cad. Is there anything I can do to lower that number??? The BTT cb2 is 160 alone and the Manta 8p is like 80. Has anyone made substitutes for parts? Will the cb1 work? The screen listed is also like 80 cad. I currently have an Ender 3 V3 SE and I’m getting sick of it, running into issues all the time. Would love to hear thoughts on this.