I have been on Town Hall 8 now for awhile and have been using a attack shown to me by a friend that is really effective and cheap and easy to use. While cheap can mean different things to different people by the way I attack and gain elixer I would call it cheap. Any way the troop set up for this attack is as follows:
(lvl 5)Giants: 16
(lvl 5)Wizards: 16
(lvl 3)Healers: 4
Barbarian King and/or Archer Queen
3 Lightning Spells
Elixer total: 128,000
The troop levels are important here as you need the giants to be able to suck up a lot of damage and the wizards need to be able to hold there own as they sometimes escape the healers reach.
There are two ways to attack with this:
1. Bases with air defenses deep inside - When you attack a base with the air defenses in close to the center you are going to want to find the side of the base that is the easiest to attack and start there. The best part about this strategy is that you can release everything at once and know that you have an almost surefire 50%. So once you find the weakest side release all of your giants and Barb King. After release 3 of your healers to stay with them. Then release all of your wizards and if you have a Archer queen now is the time. The wizards high attack will be able to defeat building very quickly. release the last healer behind them. If your healers start getting troubled by an air defense take it out with the lightning spells. Otherwise watch the chaos unfold.
2. Bases with air defenses exposed - The best way to do this is to attack the side with the easiest exposed air defense with your giants and ALL 4 healers and then watch for which way they are headed next and take out the opposite air defense. After that continue as says above.
I have level 5 wizards and giants with level 3 healers and a level 5 Barb king. Using this attack i aim for over 200,000 of gold and elixer per attack and since starting this have NEVER gotten less than 50%. I have been doing this since about May and have almost upgraded everything to the max at TH8. So as you can see it is very effective and I hope it does you well.