Did I sell too cheap?

I sold TravelHop/com six months ago for $3k. I originally bought it for $300 about 8 years ago. I listed it on Namecheap market place for $9,999, but no buyers. The buyer then contacted me directly and offered $1.8k, I countered at $3k and he immediately said he'd take it. Did I sell it for too cheap?

I keep rethinking this, did I mess up. I think a domain reseller bought it from me and he may flip it for much more. I looked at BB and they've got a couple Travel domain names that are…

Did I sell too cheap?