I received my Options set for my birthday last year and I knit with nothing else. It is easy as pie to knit straight with the circ needles and believe me, it helps when you are knitting something that starts to weigh down on your hands.
The set is $60 + shipping. If you figure you spend at least $5 a set for cheaper needles, if you purchase sizes 4-11, which is what options has, it would be $45 for a set of straights, at least that for a set of 24 inch cable circs and another $$ for a set of 32 inch cable circs. It also comes with end caps like mentioned previously to make them straights if you prefer and this lovely carrying case, which I now have been able to put everything I need in, darning needles, stitch holders, stitch counter, needle sizer, point protectors, a couple crochet hooks, ink pens, notepad, tape measure, scissors, the whole shebang. It is well worth the money spent, believe me.