Tanks are typically filled to 3000psi. And it is the regulator setup that takes this high pressure and reduces it to something that we can safely inhale.
The first stage of a regulator (what is mated to the tank valve) takes the pressure down to about 140 psi, and the 2nd stage (what is in our mouth) is what reduces it further, and has the "demand" valve (what opens the system when we begin to inhale).
There are several sized tanks. What capacity (cubic feet) are you requiring for your project?