Other things to keep in mind are the fees that are all over the place. There are a few exchanges that have coins that are not available on the others, in order to make money trading those coins, we have to beat out the trading fees and still have enough of a mainstream coin to withdraw and have made money. These can kick your butt, many small traders jump on a 100 Sat difference in price and give that money right back to the exchange in the fees here and there.
I do not consider the fees to be much of a problem if you are using the right exchange and you have a good amount to trade. I started trading with just 0.01 BTC and I was able to grow it. Those little 100,000 sats are some of the little gains I was making for a start and it was really awesome.
Bittrex will not charge you more than the percentage they would charge you on the amount you are trading normally, what is just important is the margin in the profit you are making on that trade which won't make sense if they are very small.
Yup it happens only in the method of using trading forums. It is more than a deception only because you actually have no idea what they have and what is in lacking state on the other side of the deal.
If you are told to sell your coins but in exchange of those that you not want, then eventually it leads to pay you heavy fees and hence you are left with little money completely taking the game down to zero . I think that is I like a knife on your throat or a burning stone in your wallet.