I've had my strings on my bass since I got it and want to change them (it's been like 9 months). I have a 5string. Generally, bass strings seem to be quite expensive, but I happened across these. I'm curious as to why they're so cheap. Are they crap or is this a genuinely good deal?

Also, can someone recommend a set for each of these sounds:

One warm, mellow set
One bright, percussive set

I want to try a set of each and see how significantly each can affect my tone, and just what I generally like. Must be 5string sets. Also, note that I'm in the UK. I'm guessing the same brand of strings will be available here as in the US, but just in case.