I have a few that were steals, all are G1.
I got a MIB Blurr for $40 CDN
I got a MIB Mirage for $55 CDN
I got a MLC Omega Supreme where the electronics work for $63 CDN
I got a MLC Gnaw for $50 CDN
I got a MLC Bumblebee for $10 CDN
I got all of these off of of Ebay so the prices above also include shipping which means I got the item at an actual cheaper cost.

 

G1 pre-rub Megatron misb for $155.00 shipped

 

G1 MIB complete shockwave for $70

 

g1 shockwave and g1 jetfire.shockwave was complete. for 25 bucks together.

 

I had a buddy that found out I collected TFand offered to sell me all his old ones from when he was a kid. I snagged about a 1/2 a garbage bag full of 80s transformers for about $30. Most of them were broken but I did get:

G1 Metroplex w/rubber tires & no chrome ware
G1 Chromdome w/ headmaster
G1 Mindwipe w/ headmaster

and a couple others that I can't quit seem to remember at the moment, but this was before the Metroplex Reissues & KOs had ever came out. He thought I overpaid; I thought I got a deal.

 

A few good deals here and there:

G1 Galvatron Loose/Complete with tight joints, instructions and all accessories with still working lights and sounds. A beautiful piece for only like $30 shipped.

Superlink Galvatron General for $45 shipped. Try to find that one for a good price anymore. Ugh. Cybertron Leader Galvatron on E-bay for $15 bucks. Cybertron Leader Megatron on the Junkion for $25. Cybertron Supreme Starscream for $25.

I picked up a Starscream set of both Energon figs, a Commemorative TRU re-issue G1, a Protoform movie fig, and a custom Sunstorm that the guy did from an Energon SS for $40 shipped. I already have the original G1 fig, so I sold the re-issue back up on E-bay for $40 and got the other figs for free. Can't beat that with a stick.

 

Secondhand G1 Enemy from a friend, for free.

He's an AM radio with a Rumble/Frenzy toy stuck on. He still works!

 

I found the G1 movie for a buck at a thrift store once, and I also found Cyber Stompin' Optimus at Value Village for $3.00.

 

not sure all these really count but what the hell I like to brag  

G1 Shockwave near mint and still works too- free
G1 Soundwave with a busted off head (easily fixed)- $5
G1 Blurr no gun and has 1 clip busted off the sheild but hes gotta be c-9 with no wear on him at all- free
G1 Thundercracker only missing the missiles and main wings and in really good shape- free
G1 Roadblock was only missing the inner robot and a blue visor- free
G1 Blitzwing only missing his sword 1 missile and gun and in excellent shape- free
G1 Astrotrain complete- free
G1 Perceptor 100% complete and in damned good shape -free
a 100% Armada Unicron & Car Robots Black Convoy in a trade for about $5 worth of G1 junkers
G1 Prowl no yellowing and had a busted off roof (easily fixed cant even tell it was busted)- $9
MOSC Classics Rodimus- free
MOSC Classics Mirage- free
MOSC Movie Fracture- free
MISB Alt Blue Tracks- free
Energon Superion only missing one foot plate thing- free

yea I have impeccable luck with free stuff   I have more but most of the other stuff is either broken in some way or really worn out

 

Shockwave and BBee for $5
Sunstorm and Ratchet for $5
G1 Wheeljack just mising a spoiler-Free
G1 blitzwing no acc. but had turret_Free
G1 butt beaten Shockwave-Free
Complete g1 soundwave-$5
6 complete g1 cassettes for 5 each

 

If free stuff from a friend counts, Best Buy movie 07 Ratchet-MISB, RID Megatron (the 5 in one mode) like new in box, RID Prime (the big one, but missing the large ladder, and missles) no box but still nice and electronics work. Other smaller stuff too, for free cause he was cleaning house - and absolutely refused payment. I did buy Revoltech Prime from him for 20$.

 

y

I got re-issue Red Alert for $0.01 box was all messed up and wet, toy was fine when TRU re-did their isles.

Energon for $0.49 at a brand new Target that should not have even had him, it was wayy after they would have been on shelves.

God Bless items falling out of computer systems.