The British dealer Stanley Gibbons always has some discounts under its arm. But, since November, it is a discount festival, with some arguments...
10% off the retail price on a major part of the stock: philatelic books, albums, and some United Kingdom and Commonwealth postage stamps. Non valid on the package and postage though.
End of a catalogue edition, with the new edition in printing = good times to buy if you are not a fanatic of your stamp's precise day-base value.
And, I think, you should not be with the current variations of prices and currencies. For example, the Scott catalogues saw many up variations of stamps values, some times more because of the dollar decadence these past years than because of the philatelic market. At Gibbons', it is the recent fall of the Sterling pound (less than its usual value of 1.50 euro) that motivates the seller. In a 20 November 2008 mail:
37 % down on retail prices for Japanese clients! 28% for Yankees! 16% for Europeans. Massive! But, no need to change the price stickers. These numbers are, on 20 November, the loss of value of the Sterling pound.
Finally, the British government cut the Value Added Tax (VAT) to help consumption during the Christmas season and this period of economic auto-persuasive crisis. Gibbons recalled it to its domestic market, but with a warning: in January 2009, Stanley Gibbons prices will follow the inflation rate...
Polite and courteous yes, but still merchants.