In my experience in the USA, most fast food restaurants in the suburbs give away sauces for free, but the ones in cities charge for everything. Seems to also be correlated with whether or not the fast food restaurant has self serve soda fountains versus soda poured behind the counter.
In Poland I've experienced both ones that charge you per packet, and ones where asking for a packet will have the cashier grab a bunch of them without even counting, give them to you for free, and move on to handle another customer.
That applies only to ketchup packs, though - they always charge for sauces. The only place I ever got sauce containers by handful for free was in a KFC in Shenzhen, China.
Aren't they? I had a vague impression it happened. And of course, some McDonalds' locations charge you something absurd for an extra ketchup packet.