As a free user your ad stays at the top for as long as 6 days so as to increase your leads. You can always buy packages to increase your limit to get calls/messages.
When called or a message has been sent to you (Seller) you discuss the payment preference you want to use. In cases of services 25% to 50% is first given to seller by buyer until service is complete before full payment is made. Take Note.
Once you have bought a package that gives you access to having your own payment button included in your product and would also show verified product. Though these does not apply to services.
When a verified product is purchased here it would take only 6 working days to 2 weeks interval to get products delivered to you depending on loaction too.
At the top menu you'll see the seller registration option, click it and provide all necessary details and then access your seller profile to begin selling.