It is also cheaper for them to send it free of charge.
There is no payment to chase up or process which in its self is proberbly more than the profit made. Then the labour processing the item.
Samples are quicker and generally are there for a marketing exercise so have already been taken into account in the budgets and the larger orders will pay for it.
Also you are talking about them on the internet. Free advertisement for them and worst if they are not helpful.
