In Guinea, as in much of West Africa, things are negotiable.
There are no fixed prices, for example, and one is expected to haggle. Custom, ritual, and relationships are just a few of the layers factored in sub-consciously. If you know someone well, you will get a better price. Well, why not? If someone is rich, they pay more. Makes good sense to me!
A satisfying negotiation is one in which both parties feel that they made some accomodations, but that they got the better side of the deal.
Money is fluid, and, like time, has a very different quality in Guinea.
One of my favourite anecdotes is from medical anthropologist Katherine Dettwlyer, collecting data about eating habits:
"How often do you eat meat?"
"Whenever someone kills a goat."
"How often does someone kill a goat?"
"Whenever they need the money."
"huh?"
"When someone needs money, they kill a goat and sell the meat to their neighbours. Each family buys a small amount, and when the meat is all sold, the person has the money he needs, and the rest of us have meat to eat."
...like a bank account on hooves...
(Dancing Skeletons: Life and Death in West Africa, K. Dettwyler)