I've been playing through ff8 recently and I discovered this neat little trick, and you don't loose any rare cards while doing so

learn Siren's Life/cure refine skill thing, then go out and buy LOTS of tents. 1 tent refines into 10 curaga's. simply fill each character with as many curaga's as you can. I'm almost at the end of disc one and my characters have over 3000 hp.
If you're running low on money, learn Quetzacotl's card mod, and card command, go out and transform lots of cards or win lots of cards, then convert them to items to sell. You should be able to raise more money to buy tents this way