Socket LGA 1150 is the newest, for (i3, i5 or i7)-4XXX processors. (Haswell)
Socket LGA 1155 is for the previous generations of i3, i5 and i7 processors. (Sandy Bridge or Ivy Bridge)
If you go with the previous generations, you get cheaper prices, but (slightly) less performance.
If you go with the most recent generation, Haswell, you get the highest performance, but for a higher cost.
The choice of socket also has an impact on the motherboard's price, not only on the price of the CPU.
Hope that helped