Desk research against primary sources. Figures are traced to the issuing UAE authority and linked on the page.
Gold class is not a marginally nicer version of the same fare — it doubles the Silver price outright for a seat in the first carriage, so the more efficient way to think about it is as choosing between two systems rather than paying a small premium for comfort. The AED 3.00-to-7.50 Silver range depends entirely on distance travelled, which is why a short hop across two stations and an end-to-end cross-city ride are priced nothing alike.
The AED 4 deposit on a single-trip Nol card is refundable, but only if you actually return the card — most people never do, quietly turning what looked like a cheap one-off fare into a slightly more expensive one. A Personalised Nol card avoids that entirely and is what unlocks the daily cap, AED 20 on Silver or AED 40 on Gold, which is the real saving for anyone riding the metro often enough for a single day’s fares to otherwise add up past it.