It would probably be worthwhile to pirate it even if you want everything legit when you actually publish, just because of the likelihood that you won't end up ultimately using things. Most small time game devs have lots of unfinished abandoned projects under their belt.
If you're planning on publishing games in traditional channels, I'd recommend making sure your licensing is in order. I think there are some free resources in the marketplace, but otherwise, I highly recommend paying for what you need.
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