50 or so on ebay gets you a Marshall AS50R; better amp, comes with effects, a balanced XLR input for a vocal microphone on the second channel, and more importantly a DI out. An old design, but nicely built and tough as old boots. I've swapped them loads of times for something I thought was better, but I keep coming back. If you must mike the amp, SM57s are good, but have a look at the Audix range as well. Thomann have some very cheap 'short' stands for microphones as well.
Tim