Mask Parts Trade?

[SleepyQuilter]

I am a newer user of APAP and I have a question. I am now using a brand new ComfortLite 2 mask and I like it very much. It has solved the leak problems I had with the ComfortCurve. Good for side sleeping. The mask packaging came with both nasal pillows and simple cushion, both in medium and large in individual sealed bags. Now, I have checked on cpap.com as to the price for replacing a simple cushion or nasal pillows interface and find it to be surprisingly expensive for that one piece. I was wondering if, since I use only the mediums, anyone ever trades their sealed size they do not use for the size they need on this board. It seems like it would be a good way to cut costs and make use of items that would otherwise be wasted. Is there something you all do about this? Thank you.