It is not a speculative coin.
They buy it and keep it for years, for a lot of growth.
If you can spend a lot of money and wait so much, then it will be a good investment.
If not, either forget about it, or try to trade on cheap coins.
And for this you need to be able to read graphics.
Not much only $500 I can invest now and I can hold it for 2/3 years. If I don't have much money then I will not invest in Bitcoin? I'm not clear.
With such amount I dont think so you will be making a better profit even after 2 or 3 years like you said. I suggest you to save this amount and start working on campaigns. From here you will be able to make a handsome money in few months and then add this money to the saved ones. Hence you would be having a better capital to take a healthy start. Else it will take much hard time to flourish with such low income.