It was the USA rail pass. They had a deal going on for $299 when I got mine, but that was a special.
They still sell the USA rail pass for $500, and if you’re okay with doing coach, it’s still a great deal.
You get 30 days to spend 10 segments. Each segment ends when you make a transfer. So, my Amtrak bus from Indianapolis to Galesburg, Illinois was one segment, but my train (the California Zephyr) from Galesburg to San Francisco was only one segment as well (despite being 2.5 days long).
If you plan your segments well, you can get a whole lot out of it. For instance, technically my train took me from Galesburg Illinois to Emeryville CA, which is just across the bay from San Francisco. They wanted me to use a segment to take a bus from Emeryville to San Francisco. Instead, I walked two blocks to a bus stop, and took a normal bus across for like $5, rather than using a whole segment on it (which is in-theory worth ~$50).
You have 120 days total from when you buy it, and your 30 days begins when you hop on your first segment.
Between all of the long haul trains available, you could easily travel the entire country with only the 10 segments of a single rail pass.
The worst part of it is sleeping in coach. It sucks, but if you can sleep in a recliner, you can manage it here. Melatonin helps a lot. Baby wipes are decent enough for a shower, you aren’t moving around really after all.
I’m considering doing it again this summer, albeit with slightly better prep (and having more funds ready). Food was more expensive than I anticipated. I bought a ton of protein bars and planned to have those for half of my meals, but that just wasn’t doable after 3-4 days.