While there are tons of places to rent kimonos in Kyoto (seriously, you'll see them everywhere), wargo in Gion is worth knowing about - especially if you're making a last-minute decision to join the kimono-wearing crowds. The location's pretty perfect, right in the heart of Gion where you'll want to take those classic Kyoto photos anyway.
What makes it handy is that they take same-day bookings and their pricing starts at a reasonable ¥3,300. Plus, being near both Gion-Shijo and Kawaramachi stations means you won't have to navigate too far in your rental kimono (trust me, walking in traditional Japanese wear takes some getting used to!).