Freelancing and paying taxes?

Question

Freelance

Hello!
I looked for a lot of topics - everywhere the same thing and nothing specific.
There is the issue of paying taxes.
I'm from Ukraine, I work as a system administrator in the state. the company has a small salary for a family and recently I work as a freelancer (mostly $ 400 per month) transfers go to WebMoney and then I withdraw money to a credit card
Is there a risk of tax interest?
How can the tax authorities calculate?
Who might be interested in this? The bank can hand over (meaning?) ?
Does anyone know of cases where freelancers were interested or somehow monitored accounts, sent “letters of greetings”?
On the one hand, I want to pay taxes, on the other hand, not much.
I'm not the only one (and this is not the essence of this topic).
I'm waiting for your answers.
Thank you!

Answer 1

https://youtu.be/CIvFcNHlHq8?t=6h15m10s
Who needs your $400 and even on webmoney? ;)

Answer 2

You cannot live in society and be free from society.
Register as an entrepreneur, pay taxes and sleep well.