Just a thought here - but there is a difference between testimonials and reviews - the short take is testimonials need to be curated to be most useful for a business.
But wanted to throw out a thought or two that might work to get more exposure for you. I don't know your one-off products, but let's assume it is something like antiques. If you name a NEW category called SOLD, or Previous Finds or something that 'teases" the site visitor to explore to see what they missed and compare the quality of your offerings in general. You can continue to have marketing value from those "sold" items, some customers might post a review, etc.
You might want to change to the pricing to not show - you could do this by using the Call for Pricing option (you can change the wording easily to "Sold - call for other possibilities " using the language definitions)
Additionally if you are looking for customer feedback for your wares - and you are using any of the social medial sites - they all have widgets to embed a feed and you can do that in the place of the testimonials block.
Lee
