Okay... I didn't read the entire thread as there seems to be a lot of crap (no offense intended to anyone), so i'm just gonna go ahead and give my assessment:
As it has been stated; You're level 14.
Being support in lower levels is extreme difficult and i'd suggest you leave it alone for a bit. (Not trying to discourage you, but you're only making it harder on yourself)
Sona is an interesting support, and most people seem to do it COMPLETELY wrong.
You are right. Sona eats mana for dinner. But that is just how it is! You can't go building Tear of the Goddes or Catalyst the Protector. They are not cost efficient for you.
After playing support a while, you will come to realize what you 3 mains tasks are:
1. Protect your AD carry, during laning and in teamfights.
2. Ward the map.
3. Don't feed.
Now, point 2 and 3 are pretty simple (Though you should consult a warding guide if you are serious about supporting )
Point 1 however is way more difficult, especially at lower levels where people tend to play aggressive as hell.
Don't listen too much to people in your games: They don't know what they are talking about, generally.
In your runes, as sona, you want TANKINESS. yes, tankiness.
Masteries? Tankiness and the GP10 masteries from utility.
My setup looks like this (For sona specifically)
Armor Reds, Armor Yellows, Flat MR blues, GP10 Quints.
21+ armor, 12+ MR, 3+ Gp10
Mastery: 0/9/21 or 0/13/16.
Why? You are simply going to have to conserve your mana and play safe.
When you start a match consider the lane you are in and ask yourself this one question: "Am i going to heal my carry and let him last under tower, or are we going to harass and push them to their tower?"
If 1: Max heal, play safe, don't trade too much.
If 2: Max Q, go aggressive, try to trade EARLY and make them AFRAID, then ZONE. Zoning means you... look threatening, but you don't actually do anything other than going close, UNLESS they come too close; Then you pop a Q to their face along with a Passive Q autoattack.
You need to conserve mana. All day long.
This is one of the hardest things about Sona. LEarning how to NOT run oom.
Since you are low level, try to get to 30 fast, get your rune setup, and then just practice practice and practice. If you got some good friends who are good at the game, let them coach you.
Lolpro.Com has some of the support guides written by Elementz (A tournament support).
Happy hunting.