For under $50 you could pick up a used third-party flash, a reflector (if you don't already have one) and a used copy of this book. You'd definitely get good value from that, it would open up countless possibilities for you.
https://www.amazon.com/Speedliters-Handbook-Learning-Craft-Speedlites/dp/032171105X
Then if you have the money, get a used nifty fifty as well.
You have a really nice portfolio!
Stellar shot. I don't like using my flash so I almost never do, but then I miss out on some amazing shot opportunities like this. I really should learn to use that tool. I have two 580EX II Speedlites, and even have a couple books on the topic (Speedliters Handbook and Hot Shoe Diaries) that I bought a decade ago but never really read.
I would never think to shoot 1/8000 with flash, but it certainly works here, and makes for a dramatic shot. Well done!
E-TTL doesn't know the visual intent of the photographer. Depending on what camera mode and metering zone you have selected, E-TTL could be way off-base. FEC is necessary most of the time. Don't believe me? Why don't you ask the guy who wrote the book on the subject: http://www.amazon.com/Speedliters-Handbook-Learning-Craft-Speedlites/dp/032171105X