I can get a P3S with only 2hrs flying time on it for A$ 500.oo .The problem is that I have only an old smart phone (Galaxy 2s ) . My question is ,can I fly the P3 without the smart phone ?
The P3S is a good, solid performer and an affordable entry level drone. Having said that, I feel that $500 for a P3S is at the very high end of the price range, regardless of being next-to-new with only 2 hrs of flying. At their peak, they sold for $500 new, and Walmart had them on clearance for $399 not too long ago. For that kind of money, you could likely get a good used P3A or P3 Pro. As
@Fly Dawg stated, you can fly a P3S without a phone or device but, without being able to see exactly where you are, or where you're going, or without getting any flight telemetry (altitude, speed, distance, etc.) you will have to fly it within a VERY limited visual range.
As for your Galaxy 2S, you could certainly try using it with the DJI Go app but, I doubt that the 2S would be able to support the app very well. It's been quite a while since I've seen a 2S but I'm quite certain that it's only a dual core processor being of that vintage, and probably not a very fast one. Available free memory may be a problem as well. I have an alternate recommendation to suggest. Try to negotiate a much better price for the P3S, or find a good used P3S for $300 - 350, and use the money you save to buy a newer phone with, say, a quad core processor and at least 16GB of memory to use for flying. Yeah, you can fly the phantom without a connected phone/device, but where's the fun (and safety) in that? Good luck with whichever way you go.