I second much of what's said above - the strop you posted a picture of is likely acceptable, but no better.
If you buy this, I suspect you will be looking for a replacement in the near future, which doesn't make it much of a bargain.
If you're really looking to minimize your outlay, I would ask around to see if anyone has a strop they're interested in selling.
If that doesn't work, Tony's top of the line, 3" strop only costs about 30 pounds and his 2.5" strops cost under 20 pounds. You will be much happier with either of these in the long term than the strop you posted a picuture of.
I know people always suggest that nebies ask Tony to see if they can buy a "second" from him (and I've never once heard him complain about this), I don't think its fair on Tony to do this - he's running a business after all - especially considering how reasonably priced his strops are - in particular in light of their quality.
Just my $0.02.