OO btw I recommend the Blaupunkt VA2200. I think you can still get them for around $130 shipped new.
Rated at 600x1 @ 4ohms
Btw.. for a $150 you aren't really gonna find "good amps" but you can always get decent.
This amp is supposedly reviewed pretty highly. I have one as a matter of fact, and I think it works great for that price! Hard to beat if you ask me.
http://cgi.ebay.com/Blaupunkt-VA2200...QQcmdZViewItem
This is the cheapest I could find it for now. It has raised up since they cut the price down really low for awhile.