Right now you can find the Empire Level 27088 Magnetic Base at Amazon for $10.52.
The base is no frills — it has an adjustable arm, no fine adjustment, and a clamp that should fit most dial indicators with a stem (rather than dovetail mount).
This looks like a good deal but the two negative reviews leave us wondering. It seems that both reviewers didn’t know that most non-switchable mag bases ship with a keeper on the magnet. Compounding this is the illustration showing a 1″ dial travel indicator, when for a small base like this it would be better to use a test indicator or much smaller dial travel indicator. It would also be nice to know how much holding force the magnet has.