$125,000 to buy everything? I can see why he'd ask for that, seeing as it's popular, has a growing user base, includes everything you need to continue operating.
$125,000+ to hire him or somebody else to build something similar? That's what seems slightly absurd to me.
800 hours (20 weeks) of consulting service for $125k. That's about $6.25k per week, which seems reasonable for high-quality engineering. Some folks would charge more. The key is if you believe it would take 800 hours to re-create Cheddar.
$125,000+ to hire him or somebody else to build something similar? That's what seems slightly absurd to me.