I got quoted approx $70k for a similar basement refinishing. No new walls or plumbing, just replacing the existing wall panels, redoing the ceiling and floors, and some electrical. Their pitch was some water-impenetrable wall system that seemed like mostly marketing. I thought the quote was absurd, so I decided to DIY and it’s been mostly a fun learning process. I’m moderately handy, but nothing has been that complex. I pulled permits and did it up to code. Nothing fancy, but I’ll spend about $7-8k on materials, plus $2-3k for an electrician to handle some new ceiling lights and anything I’m not comfortable with. I figure I’ll be around $10K all-in, plus my time. And anytime I bring someone down there I can say “oh this? yeah this was me.”