That looks like it's only a 100 kHz scope but the Time/Div. knob is obscured. If the DC Bal. adjustment is correct, the trace should stay in the same place when the probe is grounded and you switch through the Volts/Div. That adjustment tends to drift a lot on low end scopes and don't even play with it until the scope has a chance to temperature stabilize.
Joe
http://www.mpja.com/20MHz-Oscilloscope-Probe/productinfo/15085%20TE
Really reasonable 20MHz X1, X10 probes for $8