ok as to colors,, read the labels folks,, every single one,, including white will tell you if using several gallons to mix the cans together...
as for the brand of paint,,
if you want the truth wal marts color place is the exact same paint as a famous name brand menbtioned above, made in same batches and runs, and factory, even shipped on the same trucks with the "name brand" paint. the main difference i have found in 20 years as a professional painter,,, wal marts is about half the price. as for the power roller.. those are not a favored method by any professional painter. and are not the greatest for even coats and reliability.
get a good brush. that is comfortable to your hand. expect to pay at least 15 bucks, some of my brushes cost over 50 bucks,, but they are worth it. also,, make sure you get a high quality, ( not neccesarily priced but quility) roller cover. hte cheep paper cored covers will fuzz off onto your walls, leaving little patces of hairy paint.
personally i dont tape, but then i have 20 years of practice. i also taught dw and helpers to cut in with out taping because its not that hard to hold the brush properly and steady. also, a good razor scraper and window washing will take painbt off glass faster than you can tape it.
drop cloths are a must. if possible, buy them in a roll instead of single, and cut to lenght you need instead of all one size. news flash,, there are very few 9X 11 rooms...
also trying to walk on folded or wadded plastic sheeting with a can of paint,, not a good thing,, and speaking of cans,, get your self a brush can, they have several types on the market now, with a handle, a brush rest, etc, to make brush work easier, tryingto brush out of aregular paint can will create a mess. the lip around the lid will present a chalenge,
unless oing some fancy dry brush technique.. keep you r brush full of paint. dip the first inch or so into the paint, wipe ewach side lightly, then dip again, lightly wipe off hte excess and then paint with it,, dry brushing is number one reason that you can see brush marks around edges
edge and cut in( trim out ) first, then roll
if painting ceilings as well.. start with ceiling paint, finish ceiling, then paint trim, then walls. trust me, doing this in other ordres, can become a problem. if you tape,, peel tape asap. if letf too long, it becomes a problem