I get asked for advice on used gear and once the buyer starts to talk shipping/getting the gear I tell them this.
1) If you live in the US buy it from someone in US. Other parts of world sellers can make their own rules too.
2) If its a Steadicam and its going to cost you 4k or higher buy yourself a plane ticket and go check it out.
A) its probably as cheap to buy a $400. plane ticket as to ship one or two cases via fed ex.
3) It takes away the guesswork of what you are getting. You can check out the monitor and rig and accessories first hand and I mean put the rig together and try it on, test out the chargers and batteries.
4) take your own DSLR, if you have to just to make sure it all works as you were told.
5) Get the insurance before you leave on the trip, get the serial numbers from the owner so that when you walk out the door with the gear and on the flight home its covered.
6) take a certified check, yes go to the bank and get one. Whatever you guys agree on. But don't expect to show up with a personal check for $15k and walk away with equipment.
7) if you want to be cautious get the check for $9k on a 10k purchase and take the rest in cash or personal checks (for a small amount) just so that if something is not as you thought you can discuss it with the owner but that's up to you.
8) There is no shame in making sure you check out the gear thoroughly, make sure you're not rushed into, "oh that works just fine, I don't have the cable for it to show you."
9) Owners should make a bill of sale and list what you are getting and both of you sign two copies and you each keep one. Take a picture of your check(s).
10) Bill of sale should state if you have a check out period with the rig? Can you take it home for 3 days and if you don't like it return it? Do you pay the shipping or does the seller?
11) spelling out stuff makes for fewer arguments not more.
12) sounds stupid but ask, if I return the rig are you going to be in town next Tuesday or not?
You ship it back, it sits on the guy's porch and he's now on a job in Bolivia and the gear gets stolen now everyone is pissed!!.
13) If you are buying really expensive stuff, get a reference on the guy, who knows him/her?
14) Its your money so ask, I've been both taken and had people never think of this stuff and I don't want to have the uncomfortable moment when something goes wrong and now its all crap to figure it out.
Hey these are all ideas I bring up to buyers and sellers.
Have a good week.