I was given a commercial suture practice kit as a gift in my first year, and honestly, it was so unwieldy I only used it a couple times. The instruments were too small, too stiff, and didn't work reliably. The suture itself didn't come on a needle and threading it properly took a long time (it doesn't thread like a regular sewing needle).
Once I started clinical rotations, like Winged Scapula said, I found much easier options. I asked a nice scrub tech if I could have a few packets of suture to practice with and wound up with a bag of suture and a pair of older - but still well-working - needle drivers.