You could do it on this one for example.
http://cgi.ebay.co.uk/mountain-bike-teenagers-bike-mens-bike_W0QQitemZ270383237002QQcmdZViewItemQQptZUK_Bikes_GL?hash=item270383237002&_trksid=p3286.c0.m14&_trkparms=72%3A1688%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A0%7C293%3A1%7C294%3A50
not that you'd want to mind I'd hold out for something better.
I persoanlly have a fixed one of these
http://cgi.ebay.co.uk/DMR-Trailstar-frame_W0QQitemZ260402130959QQcmdZViewItemQQptZUK_sportsleisure_cycling_bikeparts_SR?hash=item260402130959&_trksid=p3286.c0.m14&_trkparms=72%3A1688%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50
But I'm a bit strange :-)
Apparently
@Rindle started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
You could do it on this one for example.
http://cgi.ebay.co.uk/mountain-bike-teenagers-bike-mens-bike_W0QQitemZ270383237002QQcmdZViewItemQQptZUK_Bikes_GL?hash=item270383237002&_trksid=p3286.c0.m14&_trkparms=72%3A1688%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A0%7C293%3A1%7C294%3A50
not that you'd want to mind I'd hold out for something better.
I persoanlly have a fixed one of these
http://cgi.ebay.co.uk/DMR-Trailstar-frame_W0QQitemZ260402130959QQcmdZViewItemQQptZUK_sportsleisure_cycling_bikeparts_SR?hash=item260402130959&_trksid=p3286.c0.m14&_trkparms=72%3A1688%7C66%3A2%7C65%3A12%7C39%3A1%7C240%3A1318%7C301%3A1%7C293%3A1%7C294%3A50
But I'm a bit strange :-)
Apparently