Shaymin will be blisteringly expensive, I can tell you that much. Rampardos might be relatively cheap but you'll need to invest in drawpower cards (AKA Uxie!). Scizor is pretty cheap too if you play it the Blissey way (4-4 Scizor, nothing else and a bucketload of trainers). My little sis used that in her first tournament and went 3-2 with it.
If your interested in something rogueish, try Mightyena LA with Darkrai. Fast, pretty powerful and fun.