Dear Basharat,
ln above mentioned budget you can buy home in all mentioned sectors. Let us discuss it one by one. if you are going to I-9 or I-10 you will get a home of dimensions 25 x 50 (5 marla) with normal construction like one bed on ground floor and 2 beds on first floor. You can earn approximately 22 to 25 thousand rent from it.
If you will buy a home in G-13 in that range it will be 25 x 40 size and it will be brand new.Approximately rent you can earn from that home would be around 25 to 28 thousand depends on location and construction.
In G-15 5 marla plots are not available. Smallest size available there is 30 x 60 (7.2 Marla) and you can get a brand new home of 30 x 60 in approximately 75 lac 4 beds 2 drawings 2 tv lounges 2 kitchens and momti and you can get a rent of 25th to 28 th.
for rental purpose I-9 and I-10 is fine but for investment purpose G-13 and G-15 is much better. I-9 is already developed sector and prices are stuck from last 3 years almost. But in G-15 and G-13 as they are developing sectors prices are increasing day by day. My personal opinion is that if you want a home for rental and investment purpose then go for G-13 or G-15 after 5 years your home will give you a good profit.
2nd thing is that in I-9 and i-10 you will get old construction home however in G-13 and G-15 you can get a brand new home.
The only plus point of i-9 and i-10 is that its very near to Pindi so people who mostly ravel in between Islamabad and Pindi they prefer it.
Rest God Knows Better