When you access the internet and visit a page or use an online service, your Internet Service Provider (ISP) has two choices: 1. Provide equal access at equal price regardless of user, sources address, website accessed etc. 2. Charge different rates and limit bandwidth for accessing certain locations/sites/services etc.
Net Neutrality means your ISP has to stick to number 1. It may also affect your online privacy or security and isn’t just about cost/ease of access.