I have the Raiders of the Lost Ark soundtrack. It's awesome but it took me forever to get it. I had to but it used at Half.com for fourty bucks (it's worth it). I was a little uneasy about bying a CD used but it plays fine and its in near mint condition. If you want it in mint condition you'll have to pay upwards near 100 bucks.
The only soundtrack of the Indiana Jones series I don't have is Temple of Doom (which I would love to have). If I were you I wouldn't waist my time with The Last Crusade soundtrack. It's nothing to get excited about.
Basically, if you want Raiders of the Lost Ark, you're gonna have to by it used. I looked everywhere. They just don't sell it new anymore.
The worst thing is that the people you are willing to sell theirs know that you can't get it anywhere else so they hike up their prices.
GOOD LUCK !!!