This will give you big forearms if you stick with it. You can also just make one at home with a wood stick, a rope, and a nail. Put a weight at the end, hold your arms straight in front of you, roll the weight up to the bar from the floor, roll it back down, repeat. You'll hate it. Enjoy!
https://smile.amazon.com/dp/B00HGPLEX4/ref=cm_sw_r_cp_apa_fabc_4NXHGHT6HEPPGFCNJQR2
I started doing an untrained beginner routine around 3 months ago. I had a few aches and pains starting out but my wrist pain was one that wouldn't go away. It was only in my right(dominant) wrist. It hurt more when I motioned like I was turning a key.
I tried a few things like a flex bar, grip strength trainer, and even a brace. I admit I should've tried rice buckets like in the book. Nothing was really working until someone on here recommended doing wrist roller exercises. I ended up ordering one on amazon(similar to this one) with a 10lb weight plate. It helped from day one and only got better. I ended up figuring out through trial and error that the cause was my grip and form when doing pull-ups. I gave up on getting my grip right and use rings only right now. My wrist feels so much better.
A wrist roller. They don't take up a lot of space, not very expensive and give your forearms and wrists a hell of a workout!
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2505250/#!po=11.4387 this article goes more in depth and will give you routines that work. i thought i was linking this article but the first one i posted is a nice quick intro. good luck! The exercise i depend upon most for my recovery is the wrist curl with an overhand grip. Its easy to just do in the morning till you cant stand it anymore and get relative rest for the rest of the day. I use a wrist/forearm blaster you can get cheap at walmart or other stores. http://www.amazon.com/gp/product/B00HGPLEX4/ref=pd_lpo_sbs_dp_ss_1?pf_rd_p=1944687662&pf_rd_s=lpo-top-stripe-1&pf_rd_t=201&pf_rd_i=B000XSAQP8&pf_rd_m=ATVPDKIKX0DER&pf_rd_r=1DE1Q00F678PJWX8VQEH
I find that its better to research all the information you can find and then develop your own routine after you internalize the info and fully understand whats going on with your hand and forearms