this is personally - i.e. not as a gift.
The most for me is £50 and it was Energon Unicron

I say single transformer but if it's a box set then you can still post it  

 

i spent about 200 on a custom movie leader brawl, was worth every penny!

 

About $140 for MP Wal-Mart G1 Starscream due to a scammer or else it would've been only $70-80 but eh, oh well.

 

US$135 for MP-05 Megatron. Worthy worthy~  

 

Probably the $750 I spent on a MISB Hasbro Europe Optimus Prime in late 2006 that eventually graded as AFA 80. Don't have it anymore, though.

But I've spent more than that on toys I bought that I only intended to resell.

 

$130 on a G1 Jetfire.

 

By weight? $65 on a Mini-Con.

 

umm...i feel like the cheapo here haha....$29.99 (plus taxes) for any of the movie voyager figures....LOL

 

$300 on Fort Max in 2002. Wasn't the best deal since it's missing a lot of pieces but at the time I couldn't find one with both Headmasters for under $400 so I jumped at it.

Edit: Ah hell, forgot about the 2007 Box Set which was more than that...but I'd rather not think about how much I dropped on it....

 

I can't get a job yet but one that wasn't a gift would be Wal-Mart Masterpiece Starscream for $60

 

  what Minicon was that?

 

About 5 years ago, $150 for Roadcaesar; loose.
That was the japanese brain-master combiner.
Bought all 3 as one unit.

 

£75 on Walmart Starscream.

Worth it. Hes great.

 

Think I paid 300 or 350 for my Brave Max... Oh and he's nice!  

Paid 250 for a Pre-GoBots Devil Satan 6 MIB combiner set.

Figured I'd get them out there before the big dogs start chiming in, lol. I can still remember when I first started collecting and I thought the 50 or bucks that they wanted for 20th Ann Prime was a lot. Oh how the times have changed.

DS6 is the one on the left
​

 

100 and change on MP Megs; same with Skywarp (about to pull the trigger on T-Cracker too   )

 

450 for a MIb unused Battle Gaea

 

The 300 and some for the Botcon 2005 box set, if that counts. Also, 200 for the first reissues of Convoy and Ultra Magnus. I bought them together from a seller in Hong Kong. I don't remember if Hot Rodimus came with those as well or if I bought him separately. It was too long ago. After that, it's 135-ish (can't remember) for a nice and white MIB G1 Jetfire. And after that, 90 bucks for a Brave Maximus (helluva deal nowadays. I got him several years ago).

 

Probably $150ish for MP-04 Prime when it first came out. I don't buy expensive vintage stuff.

 

Eh $80 for a G1 Screamer.

 

As shocking as it sounds to even me for as long as I have been collecting is $200.00 on Animated Magnus. Ohh Wait a second I spent like $250.00 on my TFC #0 Prime.