Advice needed on replacement rear wheel

hamcycle
hamcycle Posts: 2
edited September 2012 in Road buying advice
Hi all - first time poster AND bike newbie, so double threat!

I was hoping someone could give me some basic advice on getting a space rear wheel. The background is that I got my hybrid bike (Specialized Crosstrail 2012) at Xmas last year and wanted to make sure that I keep up its use over the coming winter... so I bought a turbo trainer. Somewhat unsurprisingly, given the knobbly tyres on the cross trail, it sounds like someone is drilling through my wall when I use it (plus it won't do my tyres any good).

So what I want to do is to get a slick training tyre... and for ease of switching, a spare rear wheel to go along with it. I want it to be cheap as possible (though I don't mind spending a little more on a decent trainer tyre). As I understand it, I will need;
  • 700c rear wheel
  • 8 speed cassette
  • 700c traner tyre

Can I get any old 700c cassette rear wheel off ebay, or do I need to consider anything re: rim size etc to fit the bike (bearing in mind it'll only be used for the trainer)? Likewise, as long as I match the speeds up, can the cassette be cheap and cheerful?

Is there anything else I would need for a quick switch or that I should look out for before I start scouring ebay for cheap Raleigh 700c wheels? :)

Thanks!