What does the P(on button enter giveaway) mean, is it good or bad - QUESTION

It is for points. You can see your current points in the upper right corner of the website.

https://www.steamgifts.com/about/faq

Scroll down to the "Entering" section to inform yourself

It is how many points it will cost you to enter that giveaway. The number of points to enter a giveaway is based on the full US Steam price for the specific game. The maximum points to enter is capped at 50 even if the game costs more. Everyone gets 6 points added to their account every 15 minutes. You can hold a max of 400 points on your account. Once you have 400, you will stop receiving points until you spend some.

P-Рубль

You are paying here with your P.