You can make your own if you want to. Some book keeping programs or some word p rocessing programs have receipts or invoices which would also work as part of their template package.

I do buy an actual receipt book and you can even sometimes find them at the dollar store. I like that they provide a duplicate. I give a receipt weekly but I also give an annual receipt that gives monthly totals. I do them weekly as a way of protecting myself from a nonpaying parent - if there is no receipt then it means you didnt' pay me. The weekly receipts are just signed and I number them starting in January as 12 - 1 (year then number sequentially) which also is a good way to track payments and if audited it would be harder for revenue canada to say I didn't claim income when there are no missing numbers.

For the annual receipt you need to give either your SIN or apply for a business number to use. All they need is a total amount paid for the year. It doesn't need to be itemized unless you want to.