It depends what you are going to shoot with it, flowers and still objects ok with 50-60mm but if you want to shoot anything live ,like bee,s insects or butterfly's,a long lens is necessary ,so as to give you a bit of room from the critter.
Then you want at least a 90mm or better still a 150mm.
The big lenses need to be tripod mounted in most cases,so if you are not using the lens on other occasions for portraits or as a good prime lens,the VR is IMHO not going to be used,so save money there.
The Sigma 150mm macro can be had for around £350.
It,s all down to what you are going to use it for....