This cartoon by Kipper Williams from The Guardian references two news stories: the departure of Bruno Guillon, CEO of luxury British bag maker Mulberry after his attempt to move upmarket by raising prices caused shares to tumble (see previous post), and George Osborne's latest Budget, in which he announced plans to allow pensioners to do what they like with their retirement savings rather than forcing them to buy an annuity.
The cartoon should be easy enough to understand once you know the background. The two women are obviously quite well-off/wealthy/rich, but the one speaking still can't afford a Mulberry handbag because they are so expensive.
To cash something in or to cash in something is to exchange something such as an insurance policy or share option for its value in money. • You will not receive the true value of your policy if you cash it in early.