Hi R-Tron, welcome to the club.
In answer to your questions.....No, you don't need a licence for CB. If you want to become a "Ham" you will need to take an exam and get a licence.
You will need a radio, power supply and an antenna.
Radios cost anywhere between £50-£300 depending on which kind you want (Multi-mode / Export are the best as they let you use all modes and are more powerful than a basic CB radio).
A power supply will cost between £50-£100 depending on size....the more powerful your radio is, the more powerful your power supply will need to be.
Antennas are available from about £35 upwards (home-base or mobile).
There are lots of other "accessories" you might want to buy....SWR meters (for tuning your antenna), spare microphones (one is supplied with the radio), etc.
How easy is it to contact people?....that depends mainly on your location and antenna. If you happen to live on high ground and have a large (1/2 wave or larger) antenna you should have no problems. Some places have many users, some don't but even with a small(ish) antenna you should be able to contact others within 20-30 miles. I live in a flat and have to use an indoor antenna but I have no problems getting contacts up to about 30 miles away (and much further, including all of Europe when conditions are good).
Hope this is helpful...if you have more questions just ask as there's always someone on the forum who will know the answers. See the link below for Knights Electrocom....many club members buy their equipment here:https://www.kcb.co.uk/contents/en-uk/d106.html