Comment by ARothfusz

I don't understand how refilling for $0.86 per wash is better than the $0.67 per wash if you use their cartridges? Or how that becomes "75 times cheaper". https://github.com/dekuNukem/bob_cassette_rewinder#cost-show...

How does this math make any sense?

  With that, the total cost per wash is:
  
  0.62p + 0.018p = 0.638p, or 0.87 US cent!
  
  We know from earlier that Bob Cassettes costs 48p (67c) per wash.
  
  Therefore, refilling it yourself is more than 75 times cheaper, resulting in a massive 98.7% cost saving compared to buying new!

Huh?