Man I am in the EXACT same boat. I found a bar for $30 at a thrift store when I was trying to get a home setup together, and it's a power bar that's about 32mm. It has OK spin considering what it is, but I'm saving up for a real bar, probably a Pendlay. I debated on whether or not to just wait on even starting o-lifting until I got a real bar, and in the end I decided if I take the risk of waiting until I get a good bar, I may lose interest and never get a good bar. I'm now 2 months into training and I'm working up to some pretty decent weights, and I'm SO glad I decided to just go for it. Yeah, hook grip's a pain in the ass, and yeah, I'm probably missing out on the benefit of good whip, but I've completely fallen in love w/ the lifts and now more than ever I'm focused on saving up for a good bar.
long story short, go for it!