Oscilloscope Advice

I'm looking to buy my first used oscilloscope in the price range of $50-$100, and have found a few options:

Hitachi V-212 2 ch. 20MHz Oscilloscope
Hitachi V-509 50MHz 2 ch. Oscilloscope
HP 1220A 15MHz Oscilloscope

I can get the V-212 for the cheapest, about $65, and the V-509 and 1220A for around $90. The V-509 is guaranteed to be in working condition, while the others power on but have not been tested. Which would you recommend as a good starter scope? I will mostly be using it for digital microcontroller work, as I'm just getting started learning AVR microcontrollers.

For digital, you need all the bandwidth you can afford.

I have a Hitachi V660 (60MHz bw) with 100MHz 'scope leads that does OK, but you can clearly see the lack of bandwidth looking at a 20MHz signal.

An ideal square wave is composed of the fundamental frequency, and ALL of the odd harmonics of the fundamental, which implies unlimited bandwidth - which of course is impossible.

The higher the bandwidth of your O'scope, the better your signals will look.

Dont buy anything that says "Powers up but not tested".

Many scopes have a calibration point that will show a 1k wave. If they cant show you SOMETHING, dont buy it.

Unless you want an expensive anchor or project.