Katy Perry on the set of her 'Teenage Dream' music video

Maidenform One Fab Fit Stripe Demi Bra – $14.99 [similar / possible exact]
.

Automatic Loveletter live at Warped Tour - July 20, 2010 by Meg Larson

BDG Pure Blue High Rise Cigarette Jean – $58 [exact]

Tay Jardine on the bus at Warped Tour 2010

Glamour Kills No. 1 Conquer Tee – $24.99 [exact]

CZ: 790,- @ RockIt
UK: £24.99 @ Route One (mens)
JP: 4,410円 @ Hasco Online (mens)

Automatic Loveletter for Incredibly Green

Glamour Kills / Incredibly Green “Green Is The New Black” Tee – $26.99 [exact – reconstructed]

Europe: € 27.90 @ Rattlesnake (mens)

We Are The In Crowd live at Warped Tour - July 17, 2010 by Ashleigh Brooke

TOMS Red Canvas Women’s Classics – $44.00 [exact]

she also owns a pair of white TOMS shoes

Kelsey and the Chaos live at Warped Tour - July 17, 2010 by Gina Nicole

Vans Checkerboard Slip On in Black/Fandango Pink – $42 [exact]

screencap from a Cady Groves video blog

So So Happy Taco Love In Blue – $22 [exact]

Lady Gaga Box Girls Grey Fitted T-Shirt – $25 [exact]

thanks last_song

[photo source unknown]

We Are The In Crowd live at Warped Tour - July 19, 2010
by Heather Teapot

here are a bunch of similar sneakers in a range of prices:

her t-shirt is by Keep-a-Breast. It’s not available online, but I assume they are selling it on Warped Tour.

Hey Monday live on the AP Tour by Erin Murphy

Xhilaration Faux Leather Scale Embossed Leggings – $12.99 [similar]

there are lots of places to buy leggings like these (search for liquid leggings, faux leather leggings or shiny leggings), but this is an excellent price.

her exact tank top was posted here