Anon,
Now that you have signed the contract, it might be more hassle than it's worth to pull out now!
Also, you took the decision to move into halls last year despite living close by, so it sounds like it's important to you to experience different aspects of university life. It's good that you have had the opportunity to live in halls and that you now have the opportunity to live with friends. It might not have been the most positive experience in halls but it was probably a useful learning experience e.g. learning to share a kitchen with strangers.
Everything is a learning curve. You might love living with your friends this year and choose to do the same next year. If it doesn't go so well, you know that you can always move back home for third year. Both are good options : )
Yes, financially you could save money by living at home, but again if it's important for you to experience what it's like living with friends, then maybe this is the best time to do it, as you might all head in different directions after university and depending on where you get work, you might find yourself living with strangers (though hopefully, they will be less messy!)!
All the best,
Oluwatosin – 2nd year student – University of Huddersfield