Reddit mentions of Office Depot Mini Marble Composition Books, 3 1/4in x 4 1/2in, Narrow Ruled, 80 Sheets, Assorted Colors (No Color Choice), pk of 4, 4170736

My gym essentials:

For the gym

• Liquid chalk. THIS SHIT IS THE BOMB FOR GRIP. It's been so great when I'm either sweating a lot or I've over-warmed my cold hands with warm breath.
  
• A notebook. I liked using this one when my workouts were more varied. Since I'm doing a more simplified routine right now, I've just been using a mini composition notebook because it's compact. A notebook is great for keeping track of your progress, keeping track of your lifts, and making notes about how you're feeling. Especially great if you find yourself having low energy days - you can take a look back at what you were eating during the day leading up to your workout and note things like your cycle, any new supplements you've tried, etc.
  
• Water bottle
  
• Carabiner with a key ring on it. I don't use this so much now that I'm only using my office gym, but being able to attach my keys to the loop on my Camelbak or the lid arm on my Nalgene water bottle is convenient.
  
  In the locker room
  
  
• Two pairs of underwear - One pair I wear specifically for lifting - spandexy boy shorts that don't breathe well enough for all-day wear but do a good job of not riding up and keeping my jiggle to a low when I run. The other pair I change into after.
  
• The rest of my outfit (top, compression leggings, shoes)
  
• Some kind of headband and/or clips and a number of hair ties.
  
• Moist wipes. I can't remember what brand I have now, but I get ones that are meant for the face. If I can't shower right often, then I use one after sweating to clean off my face then use the remainder on my chest, upper back where my barbell rests, then armpits, then towel dry everything.

Ditto. I use these myself. You can get a 3 pack from Walmart for a $1 and they easily fit in a pocket.
http://www.amazon.com/Office-Depot-Marble-Composition-Assorted/dp/B00F63LUPA/ref=sr_1_1?ie=UTF8&qid=1412947721&sr=8-1&keywords=pocket+composition+notebook