no longer sprint uses sim cards, use to be able to on older phones but sprint has caught onto that boost is boost and they are the only phones with sim cards to date and will stay that way. verizon, sprint, apple, are individual carriers, boost moble is there own carrier, what ever plan you go with that carrier you will use there own phone set of phones.
Sprint didn't "catch on" to anything. Boost mobile is the Nextel Prepaid service, this is a fact, and Sprint is a CDMA carrier that does not require nor use SIM cards. The only devices Sprint uses that have SIM cards are "world edition" devices that allow roaming outside of the country on GSM carriers. Nextel's do and always have used SIM cards. Nextel and Boost devices are interchangeable with SIM kits that they sell.
Check out a fun infographic that teaches you how to increase storage, enhance security, improve battery life and clean your device.