Matchmaking can be very very poor early on, but as you get higher and higher to 30 where you've played more games, as with any ladder, your ELO will even out and be at about the appropriate skill level.
Poppy's Q ability was already nerfed a while ago, but she's still pretty popular and a decent hero.
Tristana is also one of the better heros in the game, if you want to play a good ranged carry for only 1350 IP. Unlike Ashe, she has rocket jump which can be used both offensively and defensively as a escape mechanism, including across otherwise impassable terrain.
For people who are playing completely for free, the rune book will definitely be daunting. Tier 1 runes are the least inexpensive in terms of benefit to cost ratio , and once you hit level 10 and maybe even level 20, I highly suggest sticking with tier 1 runes until you find a bunch of characters that you like and then purchase runes accordingly.
You can probably find which runes are commonly used and which have the most "benefit per efficiency."