I've been knitting just over a month now. I did invest in a set of Chaigoo stainless interchangeable needles and I'm so glad I did.
I initially purchased the CG stainless circular set that wasn't interchangeable, now the CG's have a braided cable connecting the needles, after about 2 weeks of use the cable broke (not from a faulty product but from user misuse, just want to get that stated). So I decided to invest in a set of the interchangeables. If I'm going to be hard on circs I figured it's best economically to replace a $3 cable than a $10 set of needles when I break them.
So far it's been wonderful, I paid $80 for a small set, comes with needles sized 2 - 8, and 3 differing lengths of cable, 14" 24" or 26" maybe 32" (I'm hazy on exact sizes) and I believe the largest is 42". Don't quote me on those cable lengths. Short of it is you would end up paying $10 a piece for 21 needles that is essentially in that set.
Well worth the investment in my opinion. I can also add extras should I need them and did end up picking up a few extra sets of the 14" cables.