So, getting into a new sport means a world of gear possibilities open up. As a beginner triathlete and student I am trying to spend very little money on gear, but I still have to purchase some things to do well in my training.
Cycling

In case you haven’t heard of clipless pedals, they allow specific cycling shoes to attach securely to the pedal using a special clip. Ironically, despite the name, they do use a clipping mechanism. They are called clipless because they don’t require a traditional toe cage for foot retention.
These pedals will make the biggest difference in performance as they allow for the biker to push and pull while riding, unlike with flat pedals where you are only pushing. In this way you are able to utilize a wider range of muscles and power.

VS


Cycling is a sport in which people spend a lot of money on gear as there are many things that can aid for comfort and performance, like bike shorts and jersey, socks, sunglasses, gloves. These are usually designed with aerodynamics and comfort in mind. For example, bike shorts tend to have a cushion for glute comfort.
I chose to only buy the pedals and shoes in order to keep it affordable.
Running
Running gear is simpler, you may use the clothes you have at home, and there is a wide range of costs for runners. In the winter I have also needed a buff and gloves to keep warm, or a rain jacket when its raining, but these are useful for biking, hiking, and everyday use so I already had a buff and a pair of gloves. Something I am considering buying is a running vest, as these can help carry my keys, water, and snacks for fueling on longer runs.

Swim
So far, I have only swam in an indoor pool, and have used my old swimsuit from when I was a swimmer 7 years ago, the brand Arena makes some very durable swimsuits. I might upgrade as I continue swimming, but so far this durable swimsuit has been great. As this is my most familiar discipline, I feel comfortable in using what I have.
I hope the lakes around here are warm enough to train in this spring.

Triathlon
There is triathlon specific gear that more serious athletes use, but that at this time I am not considering for their price. Like:

