Honestly it just depends on your price range. The Fobes Debut is an excellent beginner mouthpiece but you will probably end up upgrading to a Vandoren eventually. If you are willing to spend around $100 on a mouthpiece then I would suggest getting either an M13 Lyre (which tends to play better on harder reeds like the blue box 3.5s or 4s), or a BD5 (which tends to play well on medium strength reeds like the blue box 3s).
I second the Clark Fobes Debut, although get it from Amazon as it's way cheaper:
https://www.amazon.com/Clark-Fobes-Student-Clarinet-Mouthpiece/dp/B0002HLKKK
Clarinet mouthpieces are universal, just make sure it does not say Eb, bass or alto and it should work. That being said don't just buy the cheapest one as it will likely play terribly. I would recommend a Fobes Debut or Hite Premier.
You will also need reeds and a ligature, I would recommend Vandoren 2.5 reeds, any name brand ligature is fine.
http://www.stewartellis.com/#!ID.php?page=32551
This clarinet looks exactly like my Allora, only with a different logo. The case is even the same! The fact that they say "spacer" instead of barrel says that they know nothing about clarinets. Chances are you will need to get the instrument repadded and tuned by a professional if you want it to play well, and thats a $200+ job alone.
A cheap instrument may be good in the short term, but if you plan on playing clarinet for awhile you are only hurting yourself buy buying an inferior instrument. A used brand name instrument will last far longer than a Chinese instrument.
One thing I forgot to mention, a good mouthpiece makes a HUGE difference. This is what I usually recommend to students:
https://www.amazon.com/Clark-Fobes-Student-Clarinet-Mouthpiece/dp/B0002HLKKK