I suggest you choose a
cryptocurrency exchange. I will advise you to choose the cryptocurrency exchange very carefully, because there are a lot of scammers on the Internet.
Some wallets also support cryptocurrency exchanges.
Have you see his trust? He is the scammer that you mean. Seem like this is the new way from the scammer to scam some people here. They have intention to buy/sell something and when you have done a deal you will lose your money. Common user will always use the exchange even if he is a newcomer to cryptocurrency. They should avoid to deal with someone who hasn't been known before because it is highly risk.
yes that his way to scam people contact them is just a waste of time. And the fact that price is 0.5 and he is selling it 0.30 each is so unrealistic its means for just a simple trade you will lost 40% of money you can have if you use exchange .
Who's that person want to lose that amount if they know he can have whole value of it if he selling it in exchange.