For my new to me boat I wanted AIS (receiver) if only as a little toy to play with. The boat had had its VHF removed so I needed to buy one. I decided to buy the Standard Horizon GX2400 (£340) as it has both built in GPS and AIS and only needs one Ariel for both AIS and VHF. I already own a small Garmin Echomap 55dv which is designed to be removable which I swap between my various boats. Removing it is simply a push and pull out of the mount. All you need to buy is a mount and wiring loom from Garmin (total cost £40) and you are good to go.
I wired it all up on a board at home and as I am about 15 miles from the sea drove to Felixstowe and sat on the cliffs looking at what AIS targets it would pick up. Connecting the NMEA 183 wires which I know seems scary to some was actually just a matter of connecting the Yellow on the Radio to the brown of the wiring loom of the Garmin and then the white on the radio to the black (combined negative) on the garmin and all was good.
It then takes a little while for all the AIS information about the various ships to load which it did. Looking at the AIS data on the chart plotter is much better than viewing it in the little screen on the radio.
Now to fit it in the boat.
Hope this little account proves useful to others on a budget
Dennis