I am only attending for one day. Are there single day memberships?

Yes. A Saturday membership is the same cost as pre-registration. Fridays and Sundays are cheaper. If you are unsure whether you want to come for more than one day, you may (for instance) pay for Friday and if you want to come back, pay the difference between the Friday membership and a weekend membership when you return on Saturday. You must bring your Friday badge to do this.