We have beat this to death several times, but there are often good points made each time. Food for thought.
But to address a couple items repeated in this thread;
Too low a price to be true? NOPE, not valid. Even when things were jumping in the economy prices vary A LOT.
I picked up a "4800" dollar tool box last year, before things got wacky, for 600 bucks. Number is clear, never was a lien on that box. The guy needed money, and may have had the worst add I ever saw on CL. Then my wife beat him down to half what he was asking, because she wanted to give it to me for a present and didn't want to spend more. Deal was 100% legitimate.
I buy boxes usually Craftsman, regularly from vendors for 15% of retail. How low would it be to be unreasonable or too low? Free?
As Krusty pointed out, buying a box with a lien, is not against the law. Buying one with a lien and you know it has one and you KNOW the guy won't pay it is a gray area.
Now having a box with a lien against it leaves you open to civil action.
So if the Matco/Snap-On whoever guy, pulls into your shop and hauls the box away you have only trespass and theft of non-lien tools that happen to be in your box to hold against him.
Here in California you could get him arrested, but then he could sue your tail off. So your best bet would be ask nicely for your tools back, but let him keep the box.
Of course he wouldn't do it that way. The dealer would just serve you, demanding the box back. Court would probably uphold it. The court would never allow a case of theft against you, but you would still lose the box.
If the ‘repo’ man broke into your private garage to steal it, he would be libel for years in prison. Again, he wouldn’t, he would just have a Marshal serve you. It costs very little and you ain’t gonna argue with a Marshal. Well, not twice.
If the item is advertised on CL or any other public venue, you have no obligation to assume it is stolen.
It's called the 'reasonable man' precedent. If a reasonable man would not suspect it's stolen, you have no reason to. Example, the guy wants to meet you under a bridge at midnight, you have reason to be suspicious.
The guy gives you a public add, with his phone number, then invites you to his home, it is not reasonable to automatically think the deal is crooked.
Some guys assume anyone paying one penny less than they pay for something is stealing it, or it is stolen. That is more a personal reflection on them than anything about prices.