How much can you get it for?
The biggest immediate concern (beyond frame damage, i.e. dents, etc.) is if the wheels are steel or alloy. You'll want alloy rims. If it's hard to tell if the rims are steel. See if a magnet will stick to the rim. If they do, then they're steel.
If it's a good deal it's great way to get in to learning about bikes. Pretty soon...you'll be hooked.
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