https://www.ivpn.net/blog/in-support-of-ukraine

My guess is that it allows users to circumvent national restrictions on the internet. Not sure how much that applies with Ukraine, but realistically it must do for any state that’s at war, albeit it’s perhaps not as essential as it would be in the likes of Russia or Belarus.

Could also be something to do with protecting Ukranians from Russian hackers, they’ve targeted Ukraine extensively over the last couple decades.

It doesn’t look like they have any free option (which are never truly free and generally suggest the service isn’t trustworthy). Prices are $2 per week, $6 per month, $60 per year.