Supply Stash lv50

So I just reached lv50 and I notice my lv50 supply stash requires a Perfect Iron Hammer to open. After researching a little I find the stash reward is a new weapon (DuelHammers in my case), the Hammer is a boutique item and it's single use only.

Which brings me to ask the following ^^

Do all Supply stashes over 50 require Perfect Hammers? (I've come to understand only lv50 and I think around lv80 require a hammer and later stash rewards are worth it and by far make up the price of the hammer?)

Is it worth it? (What are the exact stats on the Duelhammer? If they're better than my current weapon and the above I think is true, then I'm guessing it'd be a good idea to buy a hammer pretty much as soon as possible?)

What price can I expect to have to pay for a Hammer (I have no cash shop access whatsoever and I'm on a slight budget ^^;).
And where is the best place to buy one? (I heard you can buy gold in auction house? Can you buy perfect hammers in auction house? The only cat shop hammer I've found is one at 600k)

Any other advice?
Thank you, any help greatly appreciated ^_^