Buy some knicker elastic and make collars from that instead. The main expense would be the tag, if it got lost - but you can get small round plastic ones like luggage tags -
ONE PLASTIC NAME TAG ANCOL DOG CAT LUGGAGE INC. UK P&P on eBay (end time 04-Nov-09 11:05:53 GMT)
(just as an example - I'd never pay that much for one tag, you can get them a lot cheaper than that)

Knicker elastic also comes in white, pink or black to tone nicely with your cat! lol

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