I am looking at buying a tacx turbo trainer however I am only putting out about 200w on a bike Is this enough for a turbo trainer and if so, which tacx should I buy?I am looking at a tacx blue or satori as these are in my budget however will the satori be to hard to ride as it has a max output of about 1000watt?
I got a Tacx Flow two or three years ago, so my answer is based on this. Also I don't use it all that much...

As regards power output, I have never measured mine when riding on the open road. I have only ever got power readings when using the turbo. I generally get readings from the headunit in the 200W range (probably anything between 150 and 400 depending on effort) but the flow itself is plenty easy enough to ride. Now how closely my turbo-calculated 200W will tally with your 200W is anybody's guess, but my gut feel is that there won't be a problem with them being too hard to ride.

If you're stuck between the Blue or Sartori I can't help much there. But what I would say is that if you can afford to go up to the Flow, then although out-of-the-box it is "just" a trainer, you have the possibility to upgrade to use the Tacx VR software at a later date. I do not believe that anything beneath the Flow gives you this option, and this was my reason for settling on the Flow. 

So if that's something you might want to do in the future.... well buying the VR upgrade for the Flow will be cheaper than buying a new VR turbo.