Amazon...easily 90% of the video games I purchase are from them. Love utilizing Prime as well...so long as I get the student discounts on it for the next couple years (even though I graduated already lmao)
Steam has consistently had the best prices on almost everything. I barely even play on my PC but Amazon was a big letdown with it's shovel ware lightning deals and some things they never price matched.
Steam. I bought more games than I know what to do with and I don't think I even broke $100. Though I did enjoy the free games I snagged from Amazon due to their coupon deal.