Stay hard longer
I just googled "viagra nz" and found a medsafe article that says "you can only get viagra with a doctors prescription or from a pharmacist trained to supply sildenafil without a doctors prescription".
it's easier with a prescription, but some pharmacies will, but you have to answer some health questions and they check your blood pressure. this little checkup should be free. last year i found one chemist on K rd wanted to charge me, another was free. i think it was 'Newton Pharmacy' that was free. it was a while ago.
Put an advert on Trade me. Lol.
It's super easy to get generic Viagra from a pharmacist. I was curious and got some a year ago. Turns out 1 pill is waaaay too much for me and numbs the shit out of my face AND hard as fuck dick.
Given that it can have some quite strong effects, it's advisable to get at least a pharmacist to check you out.
Make sure to ask the pharmacy what the cost per tab is for the different strengths though. From memory back when I used to work in a pharmacy several years ago, all strengths cost the same from the wholesaler so ended up being charged the same price to the consumer. Not sure if that's the case now so it may still be cheaper to just get the 100mg and cut them unless you're happy to pay for the convenience of not having to fuck around.