Inflation

Inflation was a rise in prices.

When Amelia Ducat asked Harrison Chase to pay her for her painting, she asked for seven hundred and fifty guineas, plus inflation, making it a thousand. (TV: The Seeds of Doom)

The economy on Algol was in a terrible state due to irreversible inflation. (TV: Destiny of the Daleks)

Zaggan pound notes were absolutely inflation-proof. (COMIC: Doctor Who and the Iron Legion)

Behind the scenes
travelled back to 1964 to purchase Who merchandise at pre-inflation prices to sell at a later date. This included Dalek slippers, Dalek soaps and Dalek loo rolls. According to the Sixth Doctor, it was this transgression of the First Law of Time resulted in the Master's banishment from Gallifrey. (NOTVALID: Doctor Who? 107)