If you are interested in an AP that has decent range you may want to look at Ahri. Her Q has incredible range and her R + Flash makes it very hard to gank her.
Only real problem with her is that her Q/E are skill shots so it depends on what you want.
Wait for 50% sales. Sucks when you buy a champ then 3 days later that same champ was on sale.
I usually just buy 1 Day IP Boosts on days when I know I am gonna be playing a lot of games. I recommend buying a skin for a champ that you play a lot, if it suits your fancy.
You can also get the Digital Collectors Pack. 20 champs, a skin only available when you buy the pack, 4 Tier 3 Runes, and 1380 riot points