Can anybody recommend a reasonably priced b $ b or hotel close to copenhagen airport.
thank you.

There's a Hilton hotel right at the Copenhagen airport. I would check the Hilton website.

We stayed at Crowne Plaza: http://www.cpcopenhagen.dk/
We got a great rate on Hotwire. The hotel is a bit far from central Copenhagen but very close to the airport.

The metro will take you to the city centre within 19 minutes. And central Copenhagen is where the more inexpensive places are.

The only hotel that could be considered an airport hotel is the Hilton. The Crowne Plaza and the CabInn Metro are close, but involve a cab or train (the Crowne Plaza also has a shuttle service). Frankly, unless you got a good deal at the CP or CabInn, I would suggest heading into the city, as the difference in convenience will not be huge.