What I mean by decent is where you can really see that it is growing and it can give you profit that is enough to be reinvested.
Call me dumb but I really don't know. I'm sorry.
My only source of coins is my signature campaign. I earn about less than 0.1 BTC per month.
Any advice would be much appreciated.
in my opinion if our stretagy of trading and prediction of price calculation for future is best then we can make start trading at only very low amount of btc which is about 0.01btc it is sufficient to start trading .
0.01 would do if you are just starting up into trading and if you manage it to grow more then thats the time you should add up your bank roll so that you could able to buy coins even more and would maximize the profits. Decent investments would really depends on a certain person on which he is already contented with it.
to me if you have some good assets then 5 bitcoins will be a decent amount for trading, and that is because that if you invest some money in some alt coins and the price comes down then you will have a choice to hold it because you will have some other money to invest some where else.