WOW! I didnt realize these have gotten so expensive. I remember getting the IMAI 1/110 and the diorama several years ago for$15-$20 each.
Just hang in there with the bids. Its been my experience that sooner or later one will pop up that for whatever reason you will get for a reasonable price.
I watched the AMT Rancor for almost a year and recently got it for $35. There were only two of us bidding. The other guy either had a change of heart of forgot about it.
I've also gotten a King Zor and Johnny Reb cannon (toys not models) for under $25 when they normally go for $60 and up,
Ya gotta be patient and persistant. (easier said than done I'm sure!)