For the disability tax credit, the Canadian Centre for Policy Alternatives has estimated that it would be about $370 million a year in order to make that refundable for the people who are currently receiving it, which I believe is about 1.2 million Canadians. However, if it were made refundable, it's likely that people who could apply for it and haven't applied for it who are eligible would then apply for it. With some behaviour change, it might be more expensive than that, but it's somewhere around $370 million a year.
For the working-age tax credit, this is not something that there's a lot of research on, so we don't a have a figure for that, although it's something that we are about to do research in, and we'll update you with a figure when we have one.