How do technology reviewers get their products?

How do magazine technology reviewers get the products that they review? I mean, if a reviewer is reviewing 10 LCD TVs, that must be kind of expensive, so who provides them? Do they contact the company for the product, or do they go out to the store and buy the product with magazine-supplied money?

Except for “Consumer reports” which buys everything it reviews, companies send to reviewers all products they want reviewed (and they take them back after the review is over).

Product Review – Samsung 3D Plasma TV – January 9, 2008