But if you aren't sure if the kids will stick with it, you might want to get them a decent set of used clubs to start with, see if they like it and come back next season, then spend a bit on mid-range clubs that have some forgiveness to them. Find out whether or not they love the game before investing in a long term set.
I just went through this with my youngest a few years back. Put him in a used set of average clubs for a season so he could just hack around and figure stuff out. He loved the game and wanted to play more so I moved him up to my old set of Callaways (which was a convenient excuse to get myself some new ones!) for a season and he played and improved so much that we went and got him fitted for some Titleist T200s this season and his game really took off. But there was no way he was getting the T200s without first showing he loved the game and his play was improving to the point it was time to get him fitted.
One last piece of advice. Do pay attention to the shaft stiffness when you're getting used clubs. If your kids aren't kids, they are young men, they'll more than likely swing hard so they'll need a stiffer shaft. A regular shaft will feel like a wet spaghetti noodle in their hands. Way too whippy and not fun at all.