Hi Bro,
Jack Russell Terrier is a very high energy and super intelligent dog. You must be committed to giving this dog his daily walk. If it is not given sufficient exercise to use up those energy you may experience the following:
Tail chasing
Eating its own faeces
Destroying furnitures
It also shed large amount of hairs. If you have asthma, this dog is not suitable for you.
This is a wonderful dog if you are able to fulfill all its requirements. Do be honest to youself before taking the plunge.
After some soul-searching and you are still committed, you may want to give SPCA a visit. As far as possible, please avoid buying. There are already too many unwanted dogs given up by irresponsible owners who cannot commit sufficient time and love to the dogs.
Regards