need a good cheap modem for 8 meg adsl?

Your better off getting one from your isp not all second hand modems comes with their original drivers which can be a pain.

These are available at boot sales for just a few quid.

I got 3 for less than £10 and two of them worked well.

The other was a BT home hub, that probably works but the settings left me confused

You could try eBay, beware of stuff from Hong Kong with huge P&P costs.

As to what make, I think it really does not matter. They probably all have the same bits from the same factory packed in different plastic cases.