When I was about 13/14 I made quite a lot of money buying RRoD 360 consoles suuuuuper cheap (like srsly cheap) and fixing them up knowing that they would break again in (depending on the console) 2 weeks, 1 month, 6 months, maybe a year. I'd be careful, sometimes your warranty isn't always protection like you'd imagine. But I did sell some and still have some that work perfectly well and have been used a lot ie. I sold my friend an 05' xenon motherboard 360 that was previously RRoD'd but to this day it still works. So it depends on the console man, choose wisely.
I decided I'd just shell out the extra money for the console because it's going to be something I'm going to own for 10 years. That's equivalent to £35 per year, or about £0.10 per day - what do I get? I get a brand new console that I know comes from the factory, I know that some jackass hasn't screwed up something and I know I get that warranty from Sony; the people who made my console.