Are you selling your marker? No need for it? Getting out of the sport?
So you're selling your marker. You want a car. You have bills. It happens. We all leave the sport. We all come back to it. (most of us at least)
Since you are the seller, all you gotta do is advertise and wait for offers right?
Yeah, that's pretty much it. Do the community a favor though, and list your marker/items/tanks whatever honestly and state the condition and your terms up front. Be open to splitting a third party service and if not, make it known. Just because you think your marker is in tip top shape doesn't mean everyone out there will agree with you.
Beware of someone telling you that they will write you a $2000 check for your $500 marker and someone (either an individual or delivery service)will come pick it up along with the rest of the money from their check. This is a known scam and you'll end up liable for the full amount of that check, plus you have no marker anymore.
Send pictures of your marker and gear.. photoshop your name or username on it so there is no denying it is your marker. If you don't know how, ask.. if you have a question or are unsure about something.. ask.
If you are under 18, there's a chance your parents paid for your marker.. check with them to make sure they're cool with you pawning your gun for cash.