Actually its the guys who spend $700 on an amp and 350 for speakers that have their priorities backwards. The best amp in the world wont make crappy speakers sound good.
For example, he could buy a used PG Tantrum 1200.1 (approx 1500 watts) for less than 350. Good amp in my book, plenty for that sub (hmmm if the impedances match... too lazy too look, but point still stands). Just because he wants a $700 sub doesn't mean he has to go out and buy an overpriced JL 1000/1 too.
edit: hundreth beat me to it //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif