Honestly, the purpose of this game being "free" should be to try it out and see if you like it. If you like it and intend to play long term, you should buy some plat. This game is a product, and it should cost money just like everything else does.

Back when PL first started, you could only play the first few dungeons, and then you had to pay plat to go onto the higher level dungeons. STS obviously realized that doing it that way was not profitable enough, so they changed it to an entirely free game, but with these elixirs. Even that was not enough to save PL, so in AL they have added locked crates, which seems to be their main revenue.

So yes, they now allow you to sponge off the paying members and not spend a single dime, but don't expect it to be easy. If you buy just a little plat, you can be very competitive. I usually buy a couple 1700 plat packs each year when they are on sale, and then I make that last the rest of the year. If you divide that up monthly, that is less than $10 per month, or about the cost of a movie ticket -- certainly not something that requires you to be rich. Considering the amount of time I spend playing AL, it is certainly well worth it!