you can also use it as an excuse to start buying 6/12 packs of good beer. "I need the bottles for my beer!" once you have enough bottles, you switch to "I need to drink commercial beer for research/reference!"
I've use twist offs in a pinch (ran short on bottles and happened to have an empty 6-er of Yuengling sitting around), worked fine even with a hand capper. I don't think I'd trust anything highly carb'd or that I wanted to age for a while in them, but you can certainly use them until you build up a good supply of pry tops. just don't be surprised if you wind up with the occasional bottle that doesn't seal properly.
if you're looking for easy access, it's hard to go wrong with swing-tops. they're a little pricy ($2-3/bottle), but they make bottling a lot more bearable. they make good birthday/Christmas gifts from family that want to support your hobby but don't know what to get you.