Why nobody recommends the 6000+ series of i5 ?
Does it work it to go for i7 if I can ? If yes then which one I should go for ?
i5 Skylakes don't make a great difference with the i5 4690k, but they are the new socket of Intel, so my bad, you should go for one of them, or if you think that i7 4790k (top limit of 1150 Socket) is enough for you, well, it's your decision.
Do you want overclock or just clocked at default Ghz?
i5 6500: 210$, i5 6600k (OC): 240$
Motherboard B150: 100$ to 85$
2x4 DDR4 Ram: 45$
Total Skylake: 395$ (6600k)
Total Haswell: 295$
There is a big difference, if you are still going for the new Intel's processors, i recommend you to start with an i3. When you get more money, update to i5/i7.