Originally posted by E-Man720: You still don't get much though.
The most iv'e gotten out of any battle lately has been around 300, and when your researching their 3-4 planes its just a grind.
My recommendation to you would be to buy premium when it is a high percentage off (50+, sometimes even close to 75% off). this way you will only spend ~5,000 GE on premium (About $0.07 a day), and you will get all of the perks that come with premium, such as the increased RP and increased SL gain.
Usually the sales last for ~4-7 days, and usually only once per year, around summer time.