What is a fair amount to ask for partial refund for an item of wrong color ...?

instead of dealing with the hassle of returning &/or exchanging ?

[i bought a tablet via ebay but received the wrong color that was in the listing]
They wont think im scamming if they asked me how much of a refund I would like when I emailed them & told them they sent the wrong color. It was the sellers idea. &I have no problem taking &sending a picture of the item still in its packaging, unused to prove it.

Maybe 5% of the purchase price?