Hi a13bee,
I'm also looking for a pair of tyres for my bike, mine's is 18" in the rear and there are not to many options.
I have seen good rear tyres for 150€ like brigestone batlax.
Also I've seen a fancy rear tyre but i haven't heard of the brand before. They seem good quality and good price they are Shinko 006 Podium Radial but i don't know how they will performance.
I hope it helps.
Cheers