Mr Rivets,
B**tB**s had the Garmin c330 at $299, which is below my flinch point. They can be had slightly cheaper on the Internet. I bought one and am happy so far. Agreed that I don't see a way to enter a street without the house number.
One of the strong reasons I bought Garmin is the ability to load your own custom Points of Interest [POI]. I'm a radio geek as well as an aviation geek. I have written software that can output the transmitter locations of broadcasting stations. It is trivial to upload them to [most] Garmin mapping GPS receivers. These Garmins have no way to enter lat-long coordinates from the "panel", but the POI files are simple text files
long,lat,text
long,lat,text
etc.
Garmin's POILoader is a free download. The GPS will hold hundreds or thousands of these custom POI. Many more when you plug in an SD card. You don't have to upload to the GPS, just put the POI on an SD card.
You'll find there is a way to output lat/long text files of places you have marked on computer mapping software such as DeLorme's. Unfortunately they seem to be lat/long, rather than the long/lat that Garmin likes. You can download a very simple conversion program I wrote.
You can buy foreign mapping and put it on an SD card and still spend half as much as a fancy Nuvi. I find the c330 screen is large enough, but may not be quite as bright as you'd like in Texas sun. Sunshades are available and might help.