I have manual windows in my 2003 toyota corolla and I want to upgrade them to power windows. How easy is it and can I do it myself?

you can add power windows to it,but you,ll have to find a car like yours that has them,if you don't find all the parts you need and have to buy them separately ,it will cost more than its worth to do,check the local salvage yards for a car that has power windows first,then go from there with it,good luck on it.