Also consider the condition of the bike...
If this is a running bike in good shape, then maybe getting it for $500 makes it worth the hassle and expense of obtaining a title.
But if we're talking about a non-runner, needs work, bad tires, rusty tank, etc... then it's certainly not worth it. Not having a title isn't terminal, it just adds more expense, more hassle... gotta balance it out.
What's the condition of the bike?