From your description (a DC250) it may be that this is a second user or refurb machine and it's therefore likely to be coming from a reseller. If that's the case, I *think* that 7p is probably around the going rate for a nil commitment contract. If you were to buy a brand new 262, especially with a volume commitment, I'd expect it to be a bit cheaper than that.
A 700 will be a little bit cheaper again per click and you may be able to get it under 5p - but you will need a volume commitment. If that's gibberish jargon, ask your rep to break it down for you. Basically, if you commit to say 100K colour clicks per quarter, you'll get a better rate than if you can't commit to any volume. If you're starting out, it makes sense to go on a nil commitment and then move to a volume contract once you've built up some reliable volume. Just make sure you get the price/volume breaks in writing (and the basis for price increases). And make sure you count your fingers after you shake hands on the deal.
Hope that helps.