Accounting question for small business?

I am a small business owner. I do all my own book keeping. I am currently using wave accounting. I am a service provider so when I book dates some are this year and some are for the following year. when I book an event customers are required to put half down to hold the date. and the other half is due 30 days before the event. so even if the customer is putting money down know for a job next year that is taxable next year correct??? and that should not be income for this year?? And I should be putting that down for next years taxes?? Wave is not helpful with this at all so I was also wondering if you can recommend some free or very cheap alternatives for accounting software. Thanks