If your just starting up I wouldn't bother with any booking software...I've never used any, just stick with my diary.
At this stage I would just print out sheets with columns to write in customer details, name, address, job details etc with a view to making a customer database in perhaps Microsoft Excel in the future.
When you have a database in say 6 months or a years time you can use it to mailshot reminders to customers, either by printing them out from the database to envelopes/postcards or transfer the data to a mailshot company to send postcards for you which is less time consuming and cheaper.