I posted these in other threads, so I looked them up & copied them here. They still stand!
The first that comes to mind for me... I had my eye on a Pedulla Hexabuzz in Emerald Green at Kurosawa in Japan since November/December 2017. I had saved the link in my favorites and I'd open it occasionally to dream, looking at the pictures. My wife and I were even planning a trip to Japan in February. I was planning to go to the shop to try, and buy if I liked it. Around the middle of January, the instrument was sold. For me, that is "the one that got away" I regretted the most.
July 2019 on Reverb, there was an Alembic Epic 6 that sold for $1425. I just missed it by 2 days. I would have purchased if it was still available on my payday.
From TalkBass Classifieds, there have been a few "Basses that got away." All missed due to lack of money at the time.
This
Ritter Jupiter 6 sold by @DELACIUS
This
FBass AC6 sold by
@Mik Walker
This
Pedulla MVP 6 sold by
@DarnellBass
This
Wal Mk3 6 sold by
@BWorm
Some GAS items in general, without specific links: I've always liked the Fender Steve Bailey signature and they occasionally appear between $1500-$1800, depending on their condition. A few times, I noticed Rickenbacker 4003sw on Reverb for $1200! I never seem to have the money whenever one appears for sale. I remember a used Roscoe SKB 3006 on Guitar Center for $1500.