Hi i was wondering is it better for me to put my $150 dollars into buying
3 usb miners or putting it into a site like cex's site? What is better profit at
that small amount of money i have
I don't know what the price points you're looking at is...but do a BTC/GHS or dollar/GHS calculation. Hands down, it will be the hardware. Unfortunately, it's very hard to recover through your miner. I would just buy BTC. So if you buy BTC, then you can get into CEX.io.
Here's a few terrible things you should know about the current market condition:
1) The BTC/GHS rate is extremely high at .085 meaning you're way over paying and it's due to correct it self eventually. So if you're not watching the market closely and you miss the correction, you can lose a lot.
2) They started implemented fees Nov 12 for mining (so less BTC for you).
On a good note:
1) The GHS on Cex can be sold easily... so you will have to become a day trader to succeed!
All the best and good luck.