Using a voltmeter to measure RMS value of a sine signal with a DC offset
You can easily measure the RMS value of a sine wave + offset using a cheap multimeter. 

Most cheap (non-RMS-reading) multimeters are AC-coupled on the AC voltage ranges, so you would read the correct RMS value of the ripple only on an AC range, assuming the ripple is sinusoidal, due to the correction factor which is applied. If you happen to have one that's not AC coupled, just stick a large value film cap in series (such that Xc &lt;&lt; input resistance of your meter). 

Reading the voltage on a DC-volts range will give you the correct average value of the total signal. That also happens to be the RMS value of the offset, assuming a sinusoidal ripple. 

The RMS value of the total (refer to this derivation if you need proof) is just the quadrature sum of the two components: 

\$V_{RMS} = \sqrt{V_{DC}^2 +  V_{AC}^2}\$ 

In your example, you would read 10.00V on the DC range and 0.707V on the AC range, so the RMS value would be 10.03V.