This is my first time writting and I'm looking for info as to wheather I can use an older Ipad not an Ipad air as I dont own a newer I phone yet either... I am looking at the Phantom 3 advance..

Check the compatibility list to see if your exact model is supported or not.  You don't state what generation Ipad.    I had an original Ipad and no it would NOT work.  The OS can't run the GO app.  So I wound up buying an Ipad Air for 300 bucks.   I hear the invidia shield K1 works for these and costs around 200 bucks...

Air 2, I believe is the lowest priced full size ipad supported, and the ipad mini 2 is the lowest price mini supported.  To @QuadBart 's point The N-vidia Shield K1 seems to be the best larger option for the money (199$) as even the Wi-Fi only model has built in GPS.

I am using the Ipad 2 and work perfectly

Technically possible that the earliest iPad could work but the video relay could be real slow and processor may not be able to handle it...
The list DJI provide is a recommended list based on models they have tested that work, not to say the others will not work though try them at your own risk....as results will vary...