Kev and Warby are quite right but if it's only untill your next pay check I'd put what ever you are happy with on...just don't go mad.
I've mixed tyres loads of times and not had a problem cause one had gone before the other and I didn't have the money (or just too tight) to get them both changed. Only time I came unstuck (literally) was when I picked up a super sticky rear and had a crappy half worn Avon road runner on the front. I was straight on my ass trying to put the pegs down on a roudabout showing off in front of a bunch of kids
So once, in 25 odd years of riding aint too bad in my books
Pete.l