That's a limited budget, but it can be done if you're willing to compromise a bit. Just don't expect the best. At minimum, you need:
1)
Fixed mount VHF radio - ICOM makes a decent radio at a good price. I prefer and have Standard Horizon. You can get something good brand new for about $200. Figure on another $60-$100 for the antenna. Shakespeare Centennial VHF antennas are pretty hard to beat for around $65. You'll need to buy a mount for it, too, and probably want the rachet type (lets you lay the antenna down when needed), depending on where you physically plan to mount the antenna. The highest point on your boat is the best place to mount it for longest range and reception, since VHF is pretty much line of sight. Cholla Bay runs a repeater on Channel 26 which really helps boost your VHF range.
2)
Handheld VHF radio as a backup - Again, ICOM or West Marine around $100 or so. I use a Standard Horizon handheld. have had it for 10 years and it's bullet-proof, except when I forget to recharge it! (Duh on me!)
3)
Fishfinder/Depthfinder - Don't skimp here. You need something that's at least 500-600 watts RMS peak, dual frequency 50/200khz, and a good transducer. One that was designed with offshore use in mind, not a little Garmin that was designed for lake or bass fishing. On my old boat, I previously had a Raymarine unit (about $600) and it was fantastic. I currently have a Furuno unit and it is good, too. Figure on spending $500-700 for something decent if you buy new.
4)
GPS - I have a fixed mount chartplotter/GPS and a handheld GPS as backup. I typically use both when fishing. The handheld has better accuracy (more levels of zoom, actually) than the fixed mount unit. Go figure. You can get by with whatever you can afford here. My old boat had a small Garmin fixed mount GPS unit and it was great. However, it didn't have any chartplotting capability. Chartplotting ability buys you the ability to see all your waypoints in relation to one another. You can move the cursor to a way point and immediately know how far you currently are from it and what heading to follow to get there. My small handheld Garmin 76 even has this capability. On my dash, I have a Standard Horizon CP1000C, which is a fully bright, daylight viewable color 10 inch screen. I use it constantly when I'm underway, primarily in Highway mode. You pick a waypoint, hit GoTo, then switch to Highway mode and drive between the lines on the display. With fuel prices rising, this is invaluable to staying on course and traveling the shortest distance between point A and point B. Otherwise, you can wander all over the ocean. The Navigation display is also valuable, as it shows your ETA (Estimated Time of Arrival - important if you're trying to time your arrival with the tides), current speed, course and other important info. The cost of good GPS/Chartplotter units has come down substantially. Mine retails around $2000, but you can get something good in the $500-995 range. If you can live with grayscale rather that color, this Garmin unit is a decent buy under $400.
http://www.go2marine.com/product.do?no=156544F
This Standard Horizon is very good, 7" display, color and super functionality, but it's nearly $900.
http://www.go2marine.com/product.do?no=160457F
Shop around a bit and try to narrow down on what you feel you need. You can get by with something cheaper, but you'll appreciate some of the features and viewability (especially with eyes that are getting older) of a bigger, color screen.
Cellphone? Can be good, too. I've gotten signal on mine out to 20 miles or so. But, you have to have someone to call locally if you need help out there.
For best prices, check Ebay. You can get some good deals on new, non-current model stuff, or gently used equipmment. Use Google, too, to compare prices once you've decided on the specific models you want.
Hope this helps!
Stuart
