Florida Resident Annual Railpass. Currently $249. Sometimes they have put it on sale for $199 for a month or so each year.
With this Pass, (you MUST be a Florida Resident - some slight exceptions for military or students, I think, the rules are on the Amtrak site), you have unlimited travel on all Amtrak trains for all station stops in Florida for a full year. Go every day for a year if you want. To use it, you must show proper photo I.D. (rules on the site, again), and the Pass, and you fill out a passenger card the Conductor will give you, showing your name, Pass number, date, train number, and both origination and destination stations.
You do not and cannot reserve a seat with it - you just flash the Pass and your I.D. and get on the train. You are NOT guaranteed a seat (you might end up in the lounge car if the train is sold out), but you ARE guaranteed a ride. So far in the years we've had it and used it we did not ever end up without a seat. Wendy and I purchased the Pass for several years, but not in the last couple of years because since Sunset Limited no longer runs in Florida, they have effectively removed about a third or so of the available rail miles and stations available to visit, but they did NOT reduce the price of the Pass. Last year they didn't even lower it to $199 for the annual sale period. This year I don't know if we'll get it or not. Just remember that while it sounds like a great deal, it only IS a great deal if you USE IT a great deal.