It definitely can be pay to win although I don't spend much on it and have good success. But I've been playing for decades and consider myself a pretty skilled player. I also use proxies, basically printed out images in place of real cards, especially for new decks where I'm not sure I want to spend money on them yet.

That said, your friend didn't give you a good introduction. Your friend should have done more to help you build a solid deck and to match the power level of his deck to yours. I have many decks of different power levels for this reason, and I think good etiquette is to bring a deck that's near the power level of your opponent's, especially if they're new.

Also, buying packs isn't the best way to start out. Probably best to have a friend build you a deck or if that's not an option or to buy a precon. Most of the cards you get in packs are bad and no one really plays with them, so if you put those in your deck, you aren't going to have much success.

Or, just decide the game isn't for you. That's also valid!