[Allison K]

EV3 Kits
The core set does include at least one of each of the key components (battery, charger, motors, etc.). The line items at the bottom of the table are for if you'd like to purchase extra parts on top of those which come in the core set. For reference, I would recommend getting one additional large servo motor per team. The core kit comes with three motors total (two large, one medium), but four motors are legal and there are four motor ports.

For first year teams of young students the FLL Robot Set (which includes Core Set and Expansion Set) is reasonable. They won't be able to build anything crazy, and there will probably come a time when you wish you had a few extra Expansion Sets, but given practical matters of finance they'll be alright. A simple but reliable robot can be very successful. Plan to invest in more parts each year to continue to supplement your collection. Also, as a first year team you'll probably find other resources become your limiting factor before parts do.

Fields
Unless all of the teams are meeting at different times and thus won't have to share the field, I highly recommend having one field kit per team. Or at least one per every two teams. With the completely autonomous nature of FLL a field is absolutely necessary to use meeting time efficiently. Even if the additional fields are just on the floor without a table and borders that's better than trying to split field time.

Laptops
Much like fields, it's difficult to make efficient use of meeting time with anything less than one laptop per team. And that's only for programming, so if you plan on being able to work on the project and the robot at the same time you'll need additional computers available for the project. It's possible to work on the project without a laptop, but it's not terribly efficient.