how much is adobe suit going to cost after uni and why i have to have it legally

So If i want to continue using the Adobe softwares when I leave uni and start using them for commercial work then I will have to get a proper licence. There are a few options of costs here. I can pay for a years worth monthly for £45.73 a month or I can pay 68.60 a month as and when I need it. This sounds more expensive but actually if you only need it for 6 months total out of the year then that would be £411.60 instead of £548.78… but that means that paying for the whole year actually works out cheeper as your only paying 137.18 more for the extra 6 months. I think when I leave I will do it on a monthly basis until I get work coming in where I need to have the software for more than a couple of months of the year. When this happens i will pay for the year but monthly. I will only be able to afford this though when I have a steady job.