Depends on how much time you have for beekeeping. Rather than type it all out again, here is what I wrote to somebody else with a similar question. Just multiply all of the hours by 3 if you are going to take on 3 hives:
I think 2 hives is ideal to start with. Three strong hives is going to be demanding, but will give you a very good start with plenty of resources if one hive swarms or gets weakened for some other reason.
I presume he is selling them because he needs to give up beekeeping. You may be able to persuade him to mentor you for a short time, while you learn about beekeeping. Especially if you offer him some “compensation” for his time. My nucleus supplier offers training for beginners consisting of three visits with one to one training on your own hives for $165, just to give you an idea. I know you are NZ, and I am US, but I am sure you can work out something if you feel like it would help. I highly recommend it.
Let us know how it goes!