Like the title says mono amp. Around 160 shipped. Hifonics, MB quart etc...
I second that suggestion... I run my apsm1500 at 2 ohms to an audiopipe txx-be15 and it's very loud for one sub. Doesn't even get hot. You can get one for less than 120 if you look around, too.ASPM-1500 seems like the only amp that meets your requirments. I have one, and I like it a lot!
It runs my OA15 at 2 ohms, and oh man I pound //content.invisioncic.com/y282845/emoticons/biggrin.gif.d71a5d36fcbab170f2364c9f2e3946cb.gif
I would really like an ed.nine 1 if i could get one around 180 shipped.