I know how much I was spending on keeping a bike fit for work, that's why I bought the rohloff, it paid for itself a long time ago and since then has been saving me money
There are even cheaper ways of saving money and, more important for me, maintenance time, on a commuting bike - Sturmey Archer 3-speed or the older Sturmey Archer 5-speeds (newer ones weren't reliable). Most of my commuting from 1980 to 2012 was done on Sturmey Archer hub gears, fitted to second-hand bicycles that I got for next to nothing. Compared to derailleurs, hub gears get rid of front and rear derailleur, reduce the number of sprockets and chainrings, so easier to clean. And the chain/chainring/sprocket generally last longer, even without a Chainglider.
Pushed to the extreme, single-speed or fixed should be even cheaper, but I found these options too hard on my knees.
But the limited gearing of 3 to 5 speed hub gears is only practical if you don't live somewhere too hilly. Rohloff sorts that.
Nowadays, Nexus or Alfine 8-speed hub gears might be good alternatives in moderately hilly areas. These 8-speeds have been around for a few years, so their initial defects have mostly been corrected. They don't have the same gear range or reputation for reliability as a Rohloff, but can be had for about a tenth of the price. The Nexus SG-C6010-8RV Premium hub is currently less than £70 from SJS, so about £100 counting the shifter, sprocket, and other necessary fittings.