when i was medical student i emailed ethicon and they sent me a knot tying board.
when i was practicing suturing in medical school and in foundation, i used fruit and i went to the butchers a few times to get some meat scraps and sutured the skin back together lol.
obviously the best way is to do on real patients with someone experienced watching you and giving you feedback, so when you get to your surgical rotations/A&E ask the supervising doctors. all they can do is say no!
only warning i'd give is the danger as with all repetitive practicing, of practicing mistakes. it would be good if someone could teach you first then you practice at home than if you teach yourself wrong and practice it a million times that you can't relearn the correct way when someone finally points it out.