Self-Publishing

In Waterstone’s at lunch there’s a display advertising self-published books, with a £50 off voucher plus the opportunity to have your book displayed in Waterstone’s on Oxford Street. Looking at the publishing company’s site, authorhouse, there’s no mention of it at all, despite the voucher pointing you at the site for details . What’s even more frustrating is a complete lack of costing info; there’s no way to work out if the deal is good or not. Is it £50 off a few hundred or a few thousand?