I'm half wincing because this seems like a shameless plug, but it does fit the context. (I would have sent it directly, but there are no contact details for you in your HN profile.)

Anyway: the latest release of http://leanpub.com/freelancedeveloperbook/ has a 'Developer Deals' section, including a coupon code for 50 free Moo cards (with Moo logo on the back, or you can upgrade to get no logo). You just pay shipping - that should bring down your average card cost while starting out. You might find the other deals/promos (accountacy software, code hosting, PM tools) useful, too.