Yes, however you can order the (micro, if applicable) SIM activation kit online for $0.99 and free shipping. If you can't wait then your only option is picking up a SIM card kit from a T-Mobile store for $20.
You can also regularly get a T-Mobile prepaid phone of some variant for $20 at Walgreens, which comes with the "Activation Kit" (SIM card and secret number) as well as a terrible GSM-only phone you can throw away.