It's a good idea to use the ended listings function on eBay, that will give you a realistic idea of the price ranges. My research results, for example:
You can get a good Hameg for $50 or less, but you may have to wait months for it (at least on the US site). With these rebadged white flashy BK Precisions, Tenmas and similar, you may need to wait significantly less for a bargain. For a Tek that's in working order, be prepared to shell out above $100. For an iconic Tek in good working order, $250-$500.
Personally I just bought a Tek 2225 from a university surplus batch, all the controls are in place, no external damage, seller says is in working order and was in use until recently. He was selling scores of the things, most in far worse shape (knobs missing, etc... students are barbarians... XD) It was $130 with well below $20 for shipping. If it works good, that sounds like a fair price.