Am i gettting this right?
Obama - $79
Clinton - $19
so if I buy 10 shares in each it'll cost me $98 and I'm guarenteed to get £100 (because one of them will get the nom) or am I totally mis-understanding this?
Those are the last trades. To get shares of Obama, you may need to bid higher than 79; to get shares of Clinton, you may need to bid higher than 19.
Intrade works a little differently from the stock market in that you only need to pay a fee to trade via a "market order." If you place a "limit order," which basically means you have to wait around for someone to take the price you're offering, then you don't get charged a fee. That's meant to boost liquidity.