I couldn't get a prescription pump at first so I bought a couple on line from amazon. You can get accessories separately. The squashy ball type of pump devices don't last so I got a trigger/pistol type seperatey.
You can also get better rings and seals cheaply.
I eventually got Somarect on prescription. The advantage with the prescription one is the quality and variety of rings, choice of size tube, easier to put a ring on when required and you may get a demonstration. The advantage with the on line ones is they are far less cumbersome, can be used in the bath/shower and cost of extras is cheap. I use the online one more than the Somarect. They do exactly the same physically.
Remember take it slow, pump and release until you get max size and still release occasionally. The rings are only to maintain the erection when the pump is removed.
Cheers
Bill