Our trap is a very simple one.
Here it is (this morning actually) conveniently located next to the 'summerhouse' in which I sat sipping tea whilst identifying the moths. Very civilised.
Rather than buying a kit or a ready made trap, I decided that home-made was the way to go. Much more fun! As you can see it is made from a pop-up white washing basket (this one was from Matalan and cost £4 at the time). It came with it's own bag, so is easy to transport.
The funnel is an upturned lampshade (£2, somewhere, can't recall where).
I cut a hole in the top of the washing bin, which the inverted lampshade sits in. So far we've spent £6. The lamp assembly was cannibalised from an old desk-lamp (£0).
The bulb we use is a 15W black light (UV) (costs about £8/bulb). This is a compromise, but was chosen so as to cause little disturbance to our neighbours (we live in a rural area). As it's low energy it allows use of the trap, with a portable power pack (cost about £50), away from home, even at remote sites (with landowner permission). We chose a battery pack over a generator because of the noise, or lack of, with a battery pack. On the power pack the 15W bulb lasts all night on one charge.
I've made 2 traps and have 'back up' supplies if they fall apart.