I have just been helped by a friend and got 300 XRPs (which quickly became 299, thank you) and then I transferred 1 BTC from another address to my Ripple.com wallet.
First Ripple.com shows 299 XRP and has an exclamation sign next to it, which clicked says "Your current account is low. You must keep a minimum of 250 XRP to use all the features of a ripple."
Great! I am about to trust somebody for whom 299 < 250 ? Or is it advance warning?
But I digress, that is the new world of cryptocurrencies, some of the worst Web and UI and database programming seen in the recent history, so a site that clearly says it is beta must be excused.
Okay, so now I am trying to sell my 0.5 BTCs for some XRPs. Whether I place BTC sell order at the current bid, or in the middle between current bid and ask I always receive;
Error: Transaction failed You don't have sufficient funds