Well, I'm making a basic mining rig, 600mhz which is up gradable when I get more money. Is buying/making a mining rig worth it? I will be able to get it up to 2ghz in a few months.
I would suggest that you look into Alt Coins. I was confused by the metric that you are using (mhz and ghz), did you intend to describe that you are making a rig that will have 600 MH/s of capacity? If you do some research online, you will find that there are many web sites that can give you some earning calculations for Alt Coins. I recently began mining Alt/Scrypt coin and had to build several mining rigs, I find that the difficulty levels even there are rapidly rising.
Therefore, to address your initial question. I would say that buying or building a mining rig can definitely be worth it as long as you clearly understand all of metrics and details that comes with the territory of mining coins. This would include as another poster mentioned : Electricity Cost, but could extend to trading, choosing the right coin(s), etc..
Good Luck!
Thanks for the info bud.
I will be using a rasberry pi with 2 usb block erupters, they only mine sha cryptos, so won't be able to mine scrypt.