Halfords are doing a set of alloy rims with new tyres for £199. Look as though they should fit the 300 series [100...38].

Is it these?

http://www.halfords.com/webapp/wcs/stor ... yId_165649

I've seen worse wheels, and it's very easy to spend £200 just on tyres. Depends on what brand of tyre they're bundling in.

In the words of meg Ryan: "Yes! Yes! Yes!"

Well found that man. I've just spent £170 on four tyres, so figured this to be a bit of a deal [if they fit of course]. I used original Volvo alloys, and did a home refurb on them. Took me ages, isn't that good in the end as the paint comes up a bit thin and the rims got chipped when the covers were fitted. Looks OK, but not a patch on what a professional could do, but then they charge £75 per rim so not an option on a £350 car. If you're just running a car for cheapness, then this type of deal is outstanding.

Yeah it's a good deal, they'll definitely fit a 300. Then when the tyres wear out you'd easy get £100 for the rims from an owner of a clio/corsa/golf/etc.
4x100 is a very common pattern, but for maximum resale value get the biggest centre bore available so they'll fit all 4x100 cars.
Biggest centres are 70+mm for BMW E30 IIRC.