It's hard to understand because "cheaper" only makes sense as a relative comparison. Assuming that if, say, the service was 25% cheaper than the nominal price

It's hard to understand because "cheaper" only makes sense as a relative comparison. Assuming that if, say, the service was 25% cheaper than the nominal price last month, it is now 0.25 * 3 = 75% cheaper than the nominal price. However, it would make more sense to advertise that as a 75% discount over nominal price, so probably that's NOT what they meant. That's the only explanation that makes sense arithmetically, I believe. There cannot be another interpretation of "3x cheaper" unless you reinterpret the word "cheaper."