Sid, sid, sid. You know I can't let that slide
"cheap" beer is inexpensive (and tastes bad) because it uses less malt, hence fewer fermentables, hence less alcohol. It simply costs more to make strong beer because doing so requires more ingredients.
Most budget domestic lagers (Budmilloors, PBR, etc.) are 3.2% alcohol by volume (ABV) because that is the maximum strength allowed to be sold in grocery stores is many states. The vast majority of craft beers whether lagers or ales, exceed that amount, some by 300% (like Sierra Bigfoot and other barley wine style ale).
So, yeah, you CAN get just as blasted on cheap beer, but you have to drink many more of them, ingesting more fermented adjuncts (like rice, which gives me a screaming headache), and dispensing more, um, by products.
So, for me, even if I'm just trying to get loaded, I'd rather drink three good beers than nine bad ones. It's more enjoyable and more efficient.