If you're in a city there must be some shops you (or a mate) could just walk straight in to?
You are a little limited in choice,but you can pay cash, I've always thought that would be handy.
I get mine online as I live in the middle of the moors...they're all good in my experience, and I've used a few.
But, given the site we're on, it may be tactful to get them from whichever ones advertises here? (I don't know who that is as I'm running Adblock
)