People, especially some of my own acquaintance who are committed to the female identity, can find all kinds of reasons for spending ruboolas. One good reason is to obtain something that might have cost you m + n of such monetary units, where n is a relatively large number, but now, because of the kindness of the seller, will only cost you m of them. This counts as saving n ruboolas rather than as spending m ruboolas, even if you have no need of the article on which the m ruboolas are outlaid.
This motivation for spending is one I understand well myself and the following story explains why. When I was due to set out for Australia last November, to watch England getting soundly thrashed and the Ashes returning to their country of proper belonging, I massively over-budgeted what I would need for the trip. I did this deliberately, so that I could throw all care to the winds during my travels. In consequence, I came back from that fine country - which, just to remind you, now held those Ashes once more - very comfortably underspent on the budget, and me and WotN have ever since been enjoying the smackeroonios duly saved. We went to Florence even.
But you have to admire the acuity of my friend the Linda who has, amongst many reasons for buying handbags, not only this one - to save the ruboolas - but a more ingenious one still: to combat the terrorism.