Prior to fighting H0512, where you first meet Red XII and rescue Aeris at the Shinra tower, you can save a lot of Gil, as money is tight at the start of the game. Have your Steal Materia equipped (recommended on Tifa), and walk around where first see Jenova. There you can fight Moth Slasher (large robot with spikes) and steal Carbon Bangles (five to eight recommended) and also fight the Soldier: 3rd (normal guy) to steal the Hardedge (three to four recommended) and equip as soon as you can. You will save plenty of Gil. The Hardedge is 1500, and you can make 750 for each extra one. Carbon Bangles are 800 Gil each (sold for 400). It is difficult to steal what you want at first, however weaken the enemy and be patient. Send the other characters in the back row and make them guard.