Universal Radio tells you what comes with the Icom R75 they sell new. They include the power supply. They do not include an antenna and most tabletop receivers do not accommodate a typical telescoping whip.
However, whenever you buy a used radio there may be items missing, or the seller may include all the original items plus some extras. So you'll need to read the ad or auction carefully and ask the seller for specific information. For example, when I bought my Palstar R30C on ebay a few years ago, the seller included the 12 volt wall wart power supply (which I replaced with my own quieter floor muffin) and the excellent Palstar SP30 cube speaker.
If your budget is really tight right now, I'd recommend getting the most receiver you can for your money and don't worry about the antenna. This is probably the opposite from most advice, which usually recommends the best antenna you can get, which may improve reception with an ordinary portable. However, I tried that for awhile and found that most external antennas only overloaded my portables and tended to pick up powerful MW AM signals throughout the shortwave band. That's when I decided to upgrade from my Sony ICF-2010 portable, which is otherwise an excellent radio.
For example, the Icom R75 - like the Palstar R30-series - includes a high impedance or "Hi-Z" antenna input. All you need to use that antenna input is a bit of random wire, which you probably already have around your home.
That's all I used back in 2007 and 2008 with my Palstar. Just some magnet wire strung along the ceiling during the week, and on weekends I'd toss some wire up a nearby tree, maybe 30 feet long total. I can't leave outdoor antennas up permanently here because the maintenance crew will tear 'em down as soon as they see the wire. That's why I use magnet wire - it's thin, nearly invisible, and so cheap I don't care if they tear it down and throw it away.
Basically, the Hi-Z input with some random wire behaves just like a portable radio with a telescoping whip. It's as good, or as bad, as your local noise level. To give you an idea of what to expect from a receiver like the R75 or R30 with random wire strung along the ceiling, use your portable indoors. The tabletop with around 10 feet or so of random wire indoors will be slightly better than the portable.
Now take the portable outdoors and try to get at least 10 yards away from any building or power line. That's about what you'll get with a tabletop and some random wire *outside*, although the tabletop may sound a little better because it offers better selectivity, rejection of spurious signals, and filters which can help minimize interference from adjacent stations.
Later, you can add a better antenna. A couple of years ago I put together my own passive loop for indoor use, which is much quieter than a random wire antenna, at least below 10 MHz. There are plenty of designs online for making your own loop inexpensively. But if you're lucky and you live in an area without too much RFI, you might do just fine with the random wire antenna.
Does the icom r 75 come with everything needed, ie whip antennas and power supply. The cheapest used I can find is about 400 pounds so cannot afford any hidden costs. For example I noticed the alinco came without a power supply and they cost about 100 pounds.