Here are some eBay results that may help guide you a bit (check the descriptions for which printing they were):
The Bodleian poster is still available from their webstore (must have printed a lot of them): http://www.bodleianshop.co.uk/j-r-r-tolkien-s-hobbit-poster.html £6.99 [Update] The listing says "We sell so many, it's still in print over twenty years on!", so these current ones are reprints. I have no idea if the printing is indicated on the posters, or if the newer issues are distinguishable from other printings. My copy is in storage until I get settled further, so I cannot say for mine yet.
The postcards I seem to recall seeing for maybe $5 each or so on eBay off and on, but I cannot find any listings records at the moment.
I'll see if I can find anything else to help further over the weekend.
3988
1730013
