New gear cassette, how much?

Sconsey

Hi,
Over the weekend I decided to replace the badly buckled back wheel on my old mountain bike, bought a new back wheel but made a balls of replacing it.

When I took the clip off the gear cassette and removed it from the old wheel the whole thing kind of fell apart, the roller mechanism that the cessette sits on is now ruined (ballbearing lost, etc.).

So time to cut my losses and bring in the wheel to a bike shop, get them to fit a roller machanism and a replacement gear cassette. In fairness I don't have the right tools myself either.

Two questions: do they need the old cassette to get a right size replacement?
How much should I be expecting to pay assuming I go for the cheapest parts they have? (it's an old bike I just use for hopping around town, don't want to spend too much on it).

Thanks

blorg

No you don't need to bring the old one-unless you want the exact same gear ratios. It sounds like a screw on freewheel, cost would be in the region of 25 with a small charge for fitting, it should be an easy job.