You can still drive it. GA law says you have 30 days from date of purchase to obtain a tag - that's how new/used car owners can drive around with a paper tag on displaying nothing but a date. You do, however, need proof of insurance from day one.
I would suggest you keep the Bill of Sale (or signed/dated title) and a copy of your insurance card with you if you do venture more than a 1/4 mi from the house.
