I just checked the MasterCoinAdvisor to get a first deal started. I think I know how to send some mastercoins, but I'm not sure how I can check if the transaction was successful.
Any suggestion on this?
You and the seller should both agree on what the transaction should look like in the block chain. Once you see it show up (and assuming they didn't send the coins to someone else first!), you own the coins. There is a website for checking these transactions, but I'm told it doesn't handle valid transactions which have bitcoin change coming back to the sender. You can try that here:
http://mastercoin.bysh.me:3000/Can you confirm that there were mastercoins transferred in this transaction? How much?