No one can tell you whether it will increase or decrease.
I bought (a part of) a bitcoin last week. And, by trading it successfully to altcoins and back, i've made a reasonable profit already
. I almost doubled the amount of BTC I have now by doing that at Cryptsy (if you don't have an account yet, I think it's great if you sign up through my referallink (
https://www.cryptsy.com/users/register?refid=11356)).
I might even sell a part of my BTC soon (so that I can't loose any "real money (fiat)" if it may crash one day). But I have to admit, I was quite lucky with those trading deals