There are very few brands that do this; Zuneta provides samples of the foundations that it stocks, and Illamasqua had samples of the Skin Base available. Online perfume retailers (and particularly the independents) offer small samples at reasonable prices, and I do wish more cosmetic brands would do the same.
Instead of the beauty sample programmes that give you no choice in the product you receive (and quite often samples that you don't want) I think it'd be excellent if someone would offer foundation samples from a range of brands with a choice of shades (that you can chose yourself). I'd be happy to pay a small fee to try before buying a larger tube or pot.
What do you wish cosmetics brands would do?