first I would claim ALL income whether you issued receipts or not. Secondly, go to the Canada Revenue website and search home based businesses and specifically details as to what you can claim for your daycare. As for purchases from garage sales etc, if you didn't get the home owner to sign (with their address info) for your purchase, then I would make up a receipt for the purchases making it clear this is YOUR estimation of the amount of dollars spent and specifically name the items purchased. The CRA loves details and honesty so give them both.

Every year I have my taxes done by an accountant (for about $150.00) so then I know I am claiming everything allowed, not missing anything and this allows me to sleep at night without fear of an audit as I have done everything on the up and up. Some providers do their taxes themselves which is fine, but I just prefer an informed second opinion because I need it. LOL