This is 100 percent normal. Rank 15 is quite good for a new player. I wouldn't expect to get too much higher right away.
Your best bet right now is to look up a guide for maximizing your quest gold. It mostly involves skipping any 40-gold quest. In your case, I would also favor quests that don't require you to win games, as winning with a variety of classes will be very difficult and frustrating for you at this time.
Focus on quest gold first, and when those are done, keep on playing decks you enjoy. Also look for budget decks on this site. You can see the total dust cost in the listings, so that should help a lot.
Oh, and you'll get more bang for your buck if you save it up for bulk purchases instead of spending a little each month.
2
I can usually beat the Murloc Pally with this deck because of Everyfin is Awesome. Having a lot of fun with it. Thanks!
2
"Turn 3 thru when they surrender:"
LOL You weren't kidding. I'm 5/5 concede by turn 4 or 5.
Edit: I have now won 12/12 games with EVERY SINGLE ONE ending w/ a concede on or before turn 10.
Time to run a new deck. This is too OhPee.
4
I Fart in your General Direction!!