One day, many years ago, my grandmother gave me 50 DM (~26 EUR). Turned out she sold my Commodore 64 with my entire collection of games and accessories at a local flea market without even asking me... Oh, and I regret selling my NES so I could get the SNES...
My otrona attache. Complete with the MS-DOS upgrade and all the original papers from ordering it, along with 3-4 backups of every single program that i had for that computer, and the carrying case. I even had the invoice from ordering it.
I allowed myself to fall into the EBgames trap of trading in a good amount of PS1 games, mostly RPG's N64 and Dreamcast titles to get a Platinum Gamecube. Still love the Cube to this day but I've found myself buying back those games this past year. Not to mention that eBay sellers listing items as very good/ mint and getting a game that is all mangled up or resurfaced doesn't help. Learned my lesson though, no matter how much you want something it is just best to wait it out until you have the cash. What sucks the most is I can't really remember all it was I got rid of but little by little it is coming back. N64: Perfect Dark Resident Evil 2 Jet Force Gemini PS1: PS1 SCPH-7501 console Front Mission 3 Einhander Ehrgeiz Vagrant Story Silent Hill Legend of Dragoon (don't miss this one to be honest) Road Rash 3D Tomb Raider Tomb Raider II Tomb Raider III Dino Crisis Dino Crisis II Resident Evil 3 Dreamcast: Legacy of Kain NFL 2k Tomb Raider Chronicles Unreal Tournament Quake 3 Rush 2049 Gundam Side Story Sega GT Virtua Tennis Super Magnetic Neo Susuki Alstare Racing Monaco Grand Prix Always looking for help! So if you have anything you want to dump off I'll buy it. Boy looking back at this list now just shows how badly I got ripped. Especially with how high prices can get for these games.
I had a Vectrex which I bought when it first came out, sold it mid '90's. Also, got rid of about 20 Intellivision games when my console broke after dropping water on it in error; that was mid '80's
Since I've recently actually started keeping a lot of pirates I have so I can form a collection, I regret selling my Mario World 64 for Genesis. Probably not likely I'll come across it easily again.
I regret selling my Neo Geo AES stuff, it's hard to justify such expensive bookends, lol. They did look beautiful on the shelves though, and the games are fun as hell.
I sold practically my whole collection about 2 years after a big move and quite a few changes in my life. Sold all my import Sega systems and games, and plenty of other systems new and old. I am mainly a Sega collector but had plenty of other stuff that had piled up over the years. I got almost $3000 out of all of it in the end, but meh. It felt good for awhile, but now here I am wanting to start it up again. The goal this time is to have a more precise goal of what I buy so it doesn't get out of hand
My Saturn collection. I had over 500 games, with a complete US library. Now I have around 50. I kept (most) of the games I really loved (Panzer Dragoon trilogy, Shinrei Jusatsushu Taromaru, Blast Wind, Radiant Silvergun, Guardian Heroes), but there's a bunch of stuff I wish I could bust out now. Oddly enough, I was really itching to play Albert Odyssey a few months back. I also hate myself for selling Border Down. Stupid stupid stupid...
Sold my Game Boy w/ ~5 games, Game Gear w/ ~5 games, and ~35 good SNES games (a number worth about $25 a piece now) to Funcoland for around $120 in the late 90s. At the time I thought emulation would drive down prices and I wouldn't miss my physical copies...
I regretted selling my sealed Wonderswan FFI boxset, and last night I lucked into another sealed one for FREE! Yay. EDIT: And the Tamagotchi JPN N64 game, JPN Tamagotchi PS1 game w/virtual pet, Pokemon Green JPN, and Pokemon Silver JPN, all sealed. All Free.
I regret selling a good few of my playstation accessories because although they are not rare or expensive today a few are not that common now as they were when i bought them.
. My naomi collection . A GBA Devkit to work (should have loaned it, never needed the money, just tired of them not getting one of our kits fixed) . DoReMi Fantasy snes (boxed and in perfect condition, loved the game) . NGPC collection (I had over 12 games, tons where clam shell NGP versions). probably got a few more.
I regret selling my Z64. I didn't even need the money but I hadn't used it in months so I figured I would never use it again.
I sold my upgraded Amiga 1200 about the time DVD player were getting cheaper. All my friends had stopped playing with Amiga's by then. It had a 1gb hd, 68030 accellerator 8mb fast ram, and an external CD-rom drive, and about 100 boxed games and programs. I sold it all and got a crappy DVD player. Years later I have got back into Amiga stuff it would be worth a fortune