I will be going on a four day cruise next month. I started P90x last week and my workout schedule puts me in the recovery week while I am gone. I can work out the day we leave (Friday), and we come back in the morning on Monday. My rest day is on Sunday so the only day I would be missing would be Saturday which is supposed to be yoga. Any thoughts?

I was thinking of taking a yoga class on the cruise but it costs about 10$. I'm just not sure if I should just catch up when I get home or not.

Just do some yoga poses and stretching at the cruise. It's relaxing anyway so it goes with the schedule. I think paying $10 is pointless unless you have absolutely no idea what to do. Before you leave, look up some yoga workouts and poses you could do on your own without a video and you should be good. Everyone misses days anyways, and gladly it's just yoga. I feel like flexibility is easiest to get on your own, although I know the p90x yoga is more strength based. I'm sure you'll be fine.