TidyCal

It covers all the bases for offering a link to your availability on one or multiple calendars you have in one account. The UI could use some updating to look a little more professional and I'm not thrilled about the "minimal" advertising TidyCal injects on my booking page; the rationale being it's how they justify a one-time fee vs. subscription. Their advertising looks like I'm using a free version and makes me look like a chump. Calendly is better overall, however, I wasn't willing to pay a monthly cost. Overall, it's a good value for one account, I just which it looked more professional.