The following are downloads that available for smart phones:
wabbitemu is a free version of the TI-84 Plus C calculator but it is only available for non iphones such as android phones.
Calculate84 is a free application for the I-phones.
Link for TI-84+ free 90 days emulator you can install on your home computer is https://t.co/Yh64VVgYgB
grafNcalc83 is a $6 ap which is essentially the same as the TI-83 plus calculator that is available for iphones.