I would say that based on your upper limit of 900 miles (crow flying?) that you will need an High Frequency (HF) radio, Power supply, and an antenna/coax.
I'm going to give you new prices here on what I believe is the least expensive new equipment that you can buy:
Radio : Alinco DX-SR8T, $520 free shipping (
ALINCO DX-SR8T | 100W 160-10M HF TCVR 13.8V) Good radio, probably best on the market for the price. Covers all the HF bands with 100 watts which will give you local and world wide coverage.
Power supply : SAMLEX SEC-1223 $115 free shipping from (
SAMLEX SEC-1223 | 110V TO 13.8V 23A SWITCHING SUPPLY ) I had one of these. Lots of clean dc power. Quiet and reliable.
Antenna : Home brew this thing. You can make tons of different types of kick ass antennas for a $50 dollar roll of 14 gage copper wire from Home Depot. Dipoles rule and are the best for starting out.
Coax : this stuff runs the gamut. I recommend the best you can afford. I work for vibroplex (vibroplex.com) and we sell THE BEST consumer grade coax on the market. It is made and imported from Germany. We sell the connectors to it too. Figure good coax runs about 1 to 1.5 dollars a foot. But, you use cheap lossy coax, you will be losing a lot of your transmitted and received signal.
Antenna tuner : I recommend this one. $130 (
MFJ MFJ-941E | 300 W. 1.8-30MHZ TUNER W/BALUN ) It has a lot of features that you most likely will not use at first but will gain you huge benefits as you learn more about ham radio. With out getting too technical, an antenna is generally useful for one, maybe two bands without having to cut or add more wire to it to talk on a third band. Because of the way radio waves propagate though our sky, different times of the day require different bands for talking to the same location (bands and frequencies are a related term, but don't necessarily mean the same thing). So in order to use the same antenna across the broad range of HF bands / frequencies, you need to have an antenna tuner between the antenna and the radio in order to fool the radio into thinking the antenna is "matched" electrically to the radio. It's a bit more complicated than that, but this is the easiest way I can think to put it.
So now you have a total ham station for just a bit over 900 bucks. ( figure 100 feet of coax) And this is ALL NEW STUFF!! You can really save some money if you are prudent and buy some of it used. Power supplies and antenna tuners show up on ebay for some really good deals. The basic technology does not really change, so buying older is not going to hurt. Antennas can be dirt cheap if you build them yourself. I highly recommend new coax. It does breakdown over time, and you never know what puddle of gasoline used coax was laying in.
What about a used radio? Be careful is my best advice for that. If you don't know much about electronics and you want to save some cash and buy used, make damn sure you bring someone who knows radios with you. I don't mean some dude who had a CB years ago either. Find someone who really understands what is going on. I would also recommend staying with something no older than mid to late 90's. Lots of changes in technology since then. If you can afford to go new then do that. As for used prices, they are all over the place. I have seen 15 year old radios SELL for what the new ones cost now. I don't get it. Just be patient. Ebay is a bad place to buy used. Prices of used radios there are way over inflated. But the suckers keep shelling out the cash... Go to various ham radio store websites and get acquainted to the prices for new radios and equipment and you will have an idea of where to start.
Oh and a big thing for me... if the radio looks abused on the outside, it's probably the same for the inside. Good owners will normally keep all the manual and accessories and such. May not always keep the boxes because they can be pretty heavy. And I would NEVER buy from someone who smokes or dips / chews. I don't have personal problem with the habit as I used to do it all, but it makes for some nasty radios. The smell of smoke will never leave that radio and when it warms up, that's all you will smell.
Just find and talk to local hams. Most of us are hoarders of this stuff and have tons of it that need to be sold so we can by new stuff, haha. They can hook you up with some good deals.