wtp tires are really good... i got a wtp grippin foldable in the front and i really like it. i would get a feeling for back and gripping for front.. but now i have a khe premium street in back its good and light but latly ive been gettin lots of flats XD
I'm riding an A-bike ASM slick tyre on the back for about a year and it's done good, I use some stock Kenda tyre that came with the bike and that's been fine too.
EDIT: It's about £19.99 over here, I'm not sure how much that is in dollars.
For the back, I'd find a thin tire, with a smooth, non-directional pattern. You want a forward pattern on the front tire, and the front tire will typically be bigger. I like the looks of that Odyssey one above. I also like the Shadow Undertaker.
dont get the khes unles ur not riding on dirt, i used to have two and they both got holes in them, (and no i dont go riding through glass)i was getting constant flats. but if ur using them just for park, they feel amazing and roll so smoothly