You can help minimize waste and make a geeky statement while doing so. I've noticed more and more nerdy coffee cozies popping on Etsy, and they only cost 1-3 of your drinks from your coffee shop of choice. Here are some of my favorites:
Cuddlefish Crafts has fantastic crocheted sleeves with the Star Trek insignia. As you can see the come in different division colors; you can get the set for $39.99 or singles for $14.99.
MouthyMitts offers a Space Invader to go with your favorite morning beverage for just $14.
Dexlar Price has a printed TARDIS cozy, and it's worth getting just to make comments about having more coffee on the inside. It's $5.
Becoming Homegrown sells cozies representing the galaxy far, far away. For $5 you can choose Boba Fett or Yoda.
LuLa Creations has a cute little crochet and felt Super Mario mushroom to protect your hands for $10.
Nausicaa Distribution is bringing a little math to your coffee for $10. It may also make you crave pie (it would have that effect on me)
HG's Unique Boutique takes a little inspiration from the Hero of Canton with their Jayne inspired cozy. It can be yours for $16.
The catch is you actually have to remember to take them with you in the mornings. Mine would have to permanently live in my purse.