You'll probably have to buy secondhand. There are loads on eBay, such as this one which (at the time of writing) is still awaiting an opening �25 bid:
http://cgi.ebay.co.uk/Cannon-UC-X10-Hi-8-Video -Camera-7-tapes-2-batteries_W0QQitemZ230208013 118QQihZ013QQcategoryZ11724QQssPageNameZWDVWQQ rdZ1QQcmdZViewItem
(eBay search hint: Try separate searches for 'Hi8' and 'Hi-8'. The hyphen makes a difference).
If you'd prefer to buy a camera with a warranty, they appear quite often (usually very cheaply) in branches of Cash Converters.
Alternatively, ask at your local library for contact details for your local video group (or photographic club). They'll almost certainly have members who've still got Hi-8 equipment which they might be prepared to loan (or, if they no longer use it, to sell).
Chris