machines on Free can be a nightmare…
an example is that it took me to 2 hours to transfer a file between 3 systems via ssh.
but, it is totally doable in the end to get the job done.
but you will face many frustrating situations.
- Machines slow cause many people bruteforce
- Machines do not work properly cause someone messes something up intentionally or unintentionally
- You will find stuff that people have created, changed, that may not be part of the machine and put you in rabbit holes
These are some examples.
Having used VIP in the past i believe it is worth it, especially if you know that you will have enough time within 1-2 months to play a lot in here. As you can also have access to retired machines, so more training time 
In the end its up to you to figure out what is worth your savings.