Sorry, I am not aware of pricing in your country. Here, the M40x are around 85€ plus around 25€ for the pads, so 110€. The M50x are around 120€ (plus pads if you want them). The AKG K371 is around 115€, so the price is very similar. There is also the K361 at around 80€ but I haven’t tried them.
With my comments about preferring them to the M40x, I just mean that they are a better sounding headphone in general for my personal tastes. I have only tried them briefly but hope to get some for a more extended listen soon. You can check out @Chrono’s review here (he mentions soundstage and imaging):