How can I insulate my attic on a tight budget?
The most direct answer to your insulation question is fairly simple. Your goal should be to have insulation equaling an "R" value of 40 or above on top of the ceiling of the second floor. 

The cheapest method for a DIYer is to roll out unfaced fiberglass insulation over any existing insulation. We don't know what you have now, "R" value or type. That would be a helpful factor in determining how much more you should add.  

But with that said, here are some general guidelines: 


Standard fiberglass blanket insulation adds between 3.2 to 3.4 "R" per inch. Example: 3 1/2" insulation = R-11,  5 1/2" = R-19, etc. 
This comes in rolls either 15 1/2" or 23" wide. 


It is fairly easy to install, but precautions must be taken not to breath in any fiberglass dust or expose skin. Dust mask and light weight full clothing is good. 

Also be careful moving around in your attic. You must keep your weight on the ceiling joists, never step on the actual ceiling or you may find yourself in the room below. A few boards strategically located across a few joists can make a walkway and can be moved as you work.

If you are completely inexperienced, perhaps you can get the help of a friend with a little DIY experience to help you out. Added insulation is always a good investment and will give you a fast payback on your A/C energy costs.

If any of my fellow SE guru's have any good video tutorial links, please add them.


A video explains all this


Good Luck.