can i invest 10$ BTC ?

Buddy, It all depends upon what you want to invest in. As this is a crypto section I assume you are talking about investing in btc. Well I have been doing this from a year now since when btc was at it's ATH but you know $10 isn't a big gambler or even a trade amount but still if you would like to put $10 in btc don't do it know as it's already hyped in the last few weeks. Instead you can try to invest in other coins that are low in value..