Power supply. The key thing to avoid is crap. But, you also do not need some lab quality power supply either. I'd look for something on Amazon that had the capacity @BoxCar noted and generally good reviews. If you want a little meter or digital display, that's fine, but you don't need things like that, especially if you have your own meter available to check the output if there are problems. Antenna. Are you actually going to have the antenna inside your apartment, like near a window? If that is the case, I would buy the cheapest 1/4 wave antenna I could find and then mount it on a ground plane. You could then mount it on a baking pan or similar as long as it was at least 13" x 13" or buy something like this. OTOH the internet is full of plans to build your own 1/4 wave dipole for close to nothing. I would not worry about buying an antenna now that you can later move to a house. Once you get the house, you may well find your needs are different. Also, if you do have the antenna indoors, you should probably keep your transmit power as low as possible. Best would be under 5 watts.