I am fairly new to knitting as well and wanted to try the interchangeable needles too. Buying the fixed circular needles one set at a time is just too expensive. I didn't want to make a huge investment so I bought the Boye Needlecraft set, it was about $65 at Michale's but you can print a 40% off coupon on their site so that helps. My problem is that the needles are very straight and longer than the fixed circular needles. So, for smaller projects like baby hats and socks I can't use them. My size 8 needles with cable are 16" total length, the equivalent needles and cable from the set actually come out close to 20". Very frustrating, so I wound up buying a bulk set of DPN's which I am pretty clumsy with so far. I would steer clear of this set if you want to do smaller diameter projects like hats & socks.
Good luck, and I'm hoping to find some advice on this for my own good.