Good for them, I used to chase these kinds of deals, like a certain moderator i know of. but if you stop to think about it, spending hours to optimize for 500 - 1000 ksh is almost certainly a terrible waste compared to what you could have been doing with that time. Deal seeking always eats up many hours of time for small gains, especially this Black Friday and Cyber Monday madness. If i happened to be in Carrefour i would certainly have taken it.