I have a tank, now I need a regulator

I know there are tons of threads on reviews on regulators, etc. I want to know if I can build one for much cheaper. I don't know anything about gauges and stuff, but it looks like simple adapters and gauges you screw on.

http://www.buy.com/pr/product.aspx?sku=225951593&sellerid=34421981

All I see when I look at that is two gauges, a central gas flow chamber, an out line (for beer tube I suppose) and an in valve from the tank.

What parts do I need to make this and I'll try to find the parts and see if it's justified to build it rather than shell out $50.

My tank has a male end 3/4" threaded out line.

I think you mean this:

http://www.buy.com/pr/product.aspx?sku=225951593

edit: lol

i dont know how that didn't link correctly my bad

so is it worth it to build or should I just buy it?

and if I do buy one, what are the important specs I need to pay attention to:

Safety blow off pressure?
output barb size?
adjustable pressure? etc

I have no other keg system parts so I don't feel restricted to sizes except for my tank