Hello, the best way to buy or sell cryptocurrency is through large exchanges that have been proven over the years. These can be Binance, WhiteBIT and others. Of course, during certain transactions you will have to pay a commission, but it will come out much cheaper than losing everything in the pursuit of easy prey. It is likely that you will become such a prey. For example, in order to exchange
BTC to LTC, it is better to use online cryptocurrency exchangers.