How long do u deep fry chicken wings and at what temp should the oil be?

I agree on the 375F, and a candy thermometer is an expensive kitchen tool (like under $10). Timewise, they're done when they're done.

If you want your wings soft on the inside and crispy on the outside, cook them once at 275F, and then again at 375F. Otherwise, cook them once (for a little longer obviously) at 375F. Cook them for a few minutes on each side.

If you don't have a thermometer, you can check if the fry oil is ready by sprinkling a little flour into the oil; it should brown nicely.