Disclaimer that I'm still a noob, too.

I gave my main recommendation there, for transceiver. I haven't done the research to have a model or brand in mind, but a cheap SSB (single side-band) radio seems like it should exist, given that you can make such a device with just 7 transistors. Any remotely modern computer will be able to generate an audio signal that, when mixed up to RF the way a SSB radio does, will look like the mode of your choice. Software-wise, I've really liked working with GnuRadio so far.

Amps go for a lot more new, because they have to handle both radio frequencies and >100W powers, and do so without causing distortion. Ham radio is a dying art, so poking around for ones at estate sales or similar seems promising. 100W is generally the recommended minimum if you don't want to be frustrated.

For the feedline, assuming you're doing coax, the design tension is between bendability and DB/meter attenuation. For radio 50 ohm impedance is standard, not 75, so you can't reuse stuff from cable TV without transformers. (Impedance matching is very important, as you'll learn getting a licence)

For the various accessories you may need to connect cables, amps, antenna wires and maybe filters, Amazon. They even have the obscure stuff I've needed for my direct sample radio.

All the prefab antennas I've seen seem ludicrously expensive, given that it's a chunk of ordinary metal, so probably skip that and cut your own. Antenna recipes are all over the place on ham homepages. If you're doing a bunch of non-resonant antennas, a tuner will save you time, but they cost as much as an amp. Everything that works at the high-power end is expensive.