Stephen Lewis , May 24, 2012; 02:20 p.m.
You have plenty of choices, very inexpensively. For many years I used an old Vivitar 2800 (thyristor) on all my cameras, including a D100 and D300. It works fine for general purpose uses and runs on 4 inexpensive flashlight batteries. You can use it in the auto mode (of which there are 2) or manual mode. I bought my 2nd one last year for about $10 on the big auction site. It came with 4 filters and a 12 inch cord to fit the x synch flash socket in case it doesn't work with your hot shoe.