Easyjet charge per bag but the maximum weight is 20kg per person so even if you pay for 2 bags you cannot have more than 20kg unless you pay their extortionate rates fopr EXCESS baggage, ie the weight over 20kg. If you have paid for 4 bags, and got 100kg you are doing well. Interesting too is if you pay for one bag for 2 passengers you will get a total of 32kg. Everything is very easy to change add to on Easyjets site dont waste your time trying to talk to them!
The boarding system is SB speedy bopardsing for those who wish to pay for dedicated check and first through the gate. A is those who check in on line with hand luggage and are supposed to be called after speedy boarders then B... the rest!
You can check in on line with baggage which will get you an A boarding card but you will still have to take your luggage to the desk to check in and they will re print your boarding card but you stay in A group boarding! Its called learning to use the system!