In my experience I would say (most common to most rare)
41 back offerless
41 back Survival offer
45 back Display offer
47 back 4 Lom
21 back Secret figure
48 back revenge offer
31 back offerless
48 back offerless
32 back... never even seen a cardback...
As a ball park for any of the first four in the list I would say a C8 example would fetch £70-100, a little more for the next two. C6 examples change hands for £40-60. The 21 back is tougher to find, especially in c8 condition, most seem to be c6. I haven't seen many 31 backs for sale, when I bought mine (from Stu, years ago) he mentioned this was one of the tougher ESB Jawas to track down. Im not sure if the rarity actually means they sell for a premium though.
As for the offerless 48 and 32 back, who knows! I've never seen either one for sale, or locked in a collection.
As a general rule of thumb the ESB Jawa is the scarcest of the three films (ANH, ESB and ROTJ)
Could you post a photo of the MOC in question?
