I don't think you will save any money it costs what it costs to operate an aircraft, the only advantage is flexibility. There will be a monthly standing charge and fuel plus operating costs per hour not much different to a club aircraft plus the upfront share cost and are exposed to unforeseen repair costs. Plus you need to be a team player in a group and most groups need 100 hours at least. So I would stick with a club aircraft up to 100 hours at least you can walk away. If they have an up front payment scheme to save some money be very carful clubs fail and take students money with them.