well, my space proves you can grow a lot of bud in a space as small as a single bed. as to the missus, not much i can say there friend, i wouldnt think of offering advice on that as i would accept none when it comes to my own partner.
however..all women like to shop or save....some simple arythmatic on paper can do wonders to help ones cause
for example.
a seed £2
100 days of electric for 100 watts@ 20hrs per day aprx £20
possible yield maybe 20g (based on sweet fast bud #2)
so you have to buy 20g in £10 bags=£200
she can buy a decent pair of new shoes for the difference
The problem is less about money and more about the unnecessarily harsh penalties that go along with getting caught. Although with a small setup and just a couple small plants, I wouldn't even be on the radar.