I think a refund of $25 would be appropriate for the corrosion (ask for $50). Take the stand apart and clean and lube it and use it. Shipping this back to the seller would be a total hassle (just thinking personally here). I refunded a buyer $100 on a $600 frame because of unnoticed paint chips on my part.

And yes, all the ribbing you're getting for what you paid for shipping is unnecessary.

Scott