I haven't played Battletech in over 20 years with cardboard and was wondering what I need to start the hobby. Some people might say get the introductory box but it's out of
stock. What are the core rule books, what maps, and how many miniatures or point values of them should I get? Any other tips is appreciated. Thanks.
First of all, welcome back!
For rules, you've got a few choices depending on exactly what you want to play:
1. For just the tournament-level 'Mech rules, you can get the BattleMech Manual, which is the latest rulebook and has been condensed and includes some hardware that Total Warfare doesn't. I've heard some good things about the rules being more accessible so this might be your best bet if you want some of that giant stompy robot action without any other units to get in their way.
2. Total Warfare has the tournament-level rules for 'Mechs, infantry (including battle armor, often abbreviated BA), vehicles, and basic aerospace units including fighters and DropShips. The rules are the same as the Manual, absent some errata and newer hardware that's moved into the tournament level or been introduced since Total Warfare was originally published.
3. If you want a more abstract, simpler rule set, you can take a look at Alpha Strike, which is focused on higher-level play.
4. For older rule sets, the BattleTech Master Rules, Revised, is probably still available on DriveThruRPG and broadly speaking compatible with TW. There's a few minor changes around the edges, though, including some significant changes to damaging conventional infantry (non-battle armor). This book also includes basic construction rules for 'Mechs and vehicles that were moved to TechManual for the Total Warfare series of books. I recommend going for Total Warfare over the BattleTech Master Rules these days but it's still a solid introduction to the rules because, as noted, the core of the rules hasn't changed much over time.
The rules aren't WYSIWYG, so using whatever tokens you like is acceptable from a rules standpoint as long as you can distinguish them on the field. If you want minis, there are people around here who can give you much better advice than I can about which specific ones you might like, how to choose a faction, or the like, but around a lance (4 'Mechs or tanks) for each side is good. There's some lance boxes available from Iron Wind Metals. I say start with mediums and heavies but that gets deeper into the selection of individual 'Mechs. If you're curious who uses which specific variant to guide your purchases, the
Master Unit List is your friend, and will also give you Battle Value (Total Warfare) or all of the Alpha Strike stats (including their Point Value) if that's a guideline you want to use.
For maps, someone else can probably give you better advice than I can, but any hex map will do as a basic starting point, and there should be rules in Total Warfare for playing on miniature, non-hex terrain if I remember correctly. Alpha Strike can go on hexes or terrain (treat each hex as two inches; I can't remember if the actual hex rules are in the core book or the Companion off the top of my head).