When bidding on lego key rings, always check the price on the official lego web site first. Some so called rare ones are often highly priced on ebay but are actually quite reasonable from Lego themselves.
The worst case I noticed recently was a 'rare' 50th anniversary gold brick key chain priced at buy it now for £15. £2.99 was the price on the lego web site!!!!
Character ones such as Indiana Jones are often highly priced on ebay.
It's worth a minute to check first!!!