what sort of filter do you mean??
like a moisture filter/dryer?
You can get little ones of those from most places.
The biggest thing you need to consider is the environment you are spraying in. If there is contamination around the area you are working in, you will still get stuff in your paint jobs. so have a nice clean area to paint in, and make sure you compressor is sucking in nice clean air. Remember to give your compressor a rest too, if its only a little one, they start to get a bit hot and start to accumulate a bit of water in them if they run constantly for a while.
In my experience anyway.
