If you have Bitcoin, here is an easy way to buy XRP:

Go to  https://www.ripplewise.com/
Type in the amount of $ you want to spend, it tells you how many bitcoin that is and how many XRP you will get
Type in your Ripple address and email
Click Issue Invoice
You have 15 or 20 min to send the amount of Bitcoin to the Bitcoin address in the invoice
Shortly after you will get XRPs in your account
I have used it twice successfully

I think this is the easiest way to buy XRP by Bitcoin.