What thickness and type of insulation for the basement?

It is not cheap! but fibreglass is one of the least expensive! Thicker the better! If door opens to outside you have a walkout basement, insulate around doorjamb as well and windows if you have them? Measure to see if you have joist at 12 in on center or 16 in on center to get proper size. You need friction fit which means just that, slide it in and friction holds it in place. Cut to fit more narrow voids 3/4 in larger than measurment. If you have trouble in areas with insulation falling out because it`s not quite tight enough,you can zig zag sting across joist to hold it up! Then if you wish to drywall in future you can just board over string without any trouble. I would install poly to contain fibreglass dust in basement.

There are a couple of issues here. The basement is cold cooling the upstairs. The basement is also warmed by the upstairs to prevent things like water lines from freezing. If you insulate well enough, the basement will get colder and may freeze the pipes, not good. If you can insulate without danger of freezing things then buy at least 6" batts of insulation, no vapor barrier, with the wires that will hold the insulation up in the joists. This is pretty easy. Make sure the width of the insulation fills the opening between the joists. You will notice a big difference. If water pipes are in the joists make sure that you keep them in the insulation to keep them moderately warm. You might even put a foam insulation around them that comes in 3 or 4 foot lengths. Use 1" thick foam.

The first inch of insulation is the most cost effective. Biggest bang for the buck. Some folks might even advocate putting insulation over the joists so that they are not exposed to the air. Wood is a good conductor comparitively. I would only do as much as the joists will hold.

while you're putting the insulation into floor joists, you are able to bypass a R19, R25 or maybe R30. the better the selection, the thicker and extra useful the insulation is. yet in a floor, R13 could be fantastic. i like to apply convenience Therm. it rather is a plastic encapsulated insulation. It seems extra useful if your basement is unfinished and that i've got faith the plastic provides somewhat extra desirable protection. It costs in elementary terms a greenback or 2 extra a equipment regardless of the undeniable fact that it rather is rather worth it

fiberglass is the way to go 4" thick will do the job. Make sure you wear safety glasses and a reperator, long sleves and long pants when you do the work,

Sorry i can't be more helpful. Good luck with solving this issue. I so know what you mean...