$50/month, these days, if I'm not mistaken. (You can only use it abroad for two months at a time, but you can update your location as as far as I'm aware, and it's $/€ 50 in most places.)
Price wise, it's no comparison, but the two don't directly compete yet – power usage and antenna size of Iridium and Starlink are orders of magnitude apart (largely due to the L-band spectrum available to Iridium globally).
I believe the $50 plan used to have a pay-per-GB option for offshore use – $2 or so per GB, compared to $5 and more per MB for the competitors. But even at 300 or so, it’s orders of magnitude better for high-bandwidth use cases.